Exposure apparatus and method for producing device

ABSTRACT

A lens cleaning module is provided for a lithography system having an exposure apparatus including an objective lens. The system includes a scanning stage for supporting a wafer beneath the objective lens. A cleaning module coupling with the lithography system is provided for cleaning the objective lens in a non-manual cleaning process.

CROSS-REFERENCE

This is a Divisional of U.S. patent application Ser. No. 11/284,187filed Nov. 22, 2005 (now U.S. Pat. No. 7,388,649), which in turn is aContinuation of International Application No. PCT/JP2004/007417 whichwas filed on May 24, 2004claiming the conventional priority of Japanesepatent Application Nos. 2003-146423 filed on May 23, 2003; 2003-305280filed on Aug. 28, 2003; and 2004-049231 filed on Feb. 25, 2004. Thedisclosures of these prior applications are incorporated herein byreference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exposure apparatus and a method forproducing a device in which a substrate is exposed with a pattern via aprojection optical system and a liquid.

2. Description of the Related Art

Semiconductor devices and liquid crystal display devices are produced bythe so-called photolithography technique in which a pattern formed on amask is transferred onto a photosensitive substrate. The exposureapparatus, which is used in the photolithography step, includes a maskstage for supporting the mask and a substrate stage for supporting thesubstrate. The pattern on the mask is transferred onto the substrate viaa projection optical system while successively moving the mask stage andthe substrate stage. In recent years, it is demanded to realize thehigher resolution of the projection optical system in order to respondto the further advance of the higher integration of the device pattern.As the exposure wavelength to be used is shorter, the resolution of theprojection optical system becomes higher. As the numerical aperture ofthe projection optical system is larger, the resolution of theprojection optical system becomes higher. Therefore, the exposurewavelength, which is used for the exposure apparatus, is shortened yearby year, and the numerical aperture of the projection optical system isincreased as well. The exposure wavelength, which is dominantly used atpresent, is 248 nm of the KrF excimer laser. However, the exposurewavelength of 193 nm of the ArF excimer laser, which is shorter than theabove, is also practically used in some situations. When the exposure isperformed, the depth of focus (DOF) is also important in the same manneras the resolution. The resolution R and the depth of focus δ arerepresented by the following expressions respectively.R=k ₁ ·λ/NA  (1)δ=±k ₂ ·λ/NA ²  (2)

In the expressions, λ represents the exposure wavelength, NA representsthe numerical aperture of the projection optical system, and k₁ and k₂represent the process coefficients. According to the expressions (1) and(2), the following fact is appreciated. That is, when the exposurewavelength λ is shortened and the numerical aperture NA is increased inorder to enhance the resolution R, then the depth of focus δ isnarrowed.

If the depth of focus δ is too narrowed, it is difficult to match thesubstrate surface with respect to the image plane of the projectionoptical system. It is feared that the margin is insufficient during theexposure operation. Accordingly, the liquid immersion method has beensuggested, which is disclosed, for example, in International PublicationNo. 99/49504 as a method for substantially shortening the exposurewavelength and widening the depth of focus. In this liquid immersionmethod, the space between the lower surface of the projection opticalsystem and the substrate surface is filled with a liquid such as wateror any organic solvent so that the resolution is improved and the depthof focus is magnified about n times by utilizing the fact that thewavelength of the exposure light beam in the liquid is 1/n as comparedwith that in the air (n represents the refractive index of the liquid,which is about 1.2 to 1.6 in ordinary cases).

However, the conventional technique as described above involves thefollowing problem. The exposure apparatus, which is disclosed inInternational Publication No. 99/49504, is constructed such that theliquid is supplied and recovered to form the liquid immersion area on apart of the substrate. In the case of this exposure apparatus, forexample, when the substrate stage is moved to the load/unload positionin order to unload the substrate having been placed on the substratestage and load a new substrate in a state in which the liquid in theliquid immersion area is not recovered sufficiently after the completionof the liquid immersion exposure, there is such a possibility that theliquid, which remains on (adheres to) the end portion of the projectionoptical system, the liquid supply nozzle, and/or the liquid recoverynozzle, may fall onto surrounding units and members including, forexample, the guide surface of the stage and the reflecting surface forthe interferometer for the stage.

Further, when the liquid remains on the optical element disposed at theend portion of the projection optical system, the remaining liquidleaves any adhesion trace (so-called water mark) on the optical elementdisposed at the end portion of the projection optical system after theevaporation of the remaining liquid. There is such a possibility thatany harmful influence may be exerted on the pattern to be formed on thesubstrate during the exposure process to be subsequently performed. Itis also assumed that the liquid immersion area is formed during anyprocess other than the exposure process, i.e., when the reference markmember and/or the reference plane member arranged around the substrateon the substrate stage is used. In such a situation, there is such apossibility that the liquid in the liquid immersion area cannot berecovered sufficiently, the adhesion trace may remain on the member asdescribed above, and the liquid remaining on the member as describedabove may be scattered.

SUMMARY OF THE INVENTION

The present invention has been made taking the foregoing circumstancesinto consideration, an object of which is to provide an exposureapparatus capable of forming a desired device pattern on a substrate bysufficiently removing any unnecessary liquid when the pattern isprojected onto the substrate to perform the exposure via a projectionoptical system and the liquid, and a method for producing a device basedon the use of the exposure apparatus.

In order to achieve the object as described above, the present inventionadopts the following constructions.

According to a first aspect of the present invention, there is providedan exposure apparatus which projects an image of a pattern onto asubstrate through a liquid to expose the substrate therewith; theexposure apparatus comprising a projection optical system which projectsthe image of the pattern onto the substrate; and a liquid-removingmechanism which removes the liquid remaining on a part arranged in thevicinity of an image plane of the projection optical system.

According to the present invention, any unnecessary liquid, whichremains on the part arranged in the vicinity of the image plane of theprojection optical system, including, for example, an optical elementdisposed at the end portion of the projection optical system, areference member for positioning the shot area, various sensors, alight-transmitting optical member, and a nozzle of the liquid supplyand/or the liquid recovery mechanism, is removed by the liquid-removingmechanism. Accordingly, it is possible to avoid the scattering and thefalling of the remaining liquid and the occurrence of the adhesion trace(water mark) on the part as described above. Therefore, it is possibleto form the desired pattern accurately on the substrate.

According to a second aspect of the present invention, there is providedan exposure apparatus which exposes a substrate by forming a liquidimmersion area on a part of the substrate and projecting an image of apattern onto the substrate through a liquid in the liquid immersionarea, the exposure apparatus comprising:

-   -   a projection optical system which projects the image of the        pattern onto the substrate;    -   a substrate stage which is movable while holding the substrate;    -   a liquid supply mechanism which supplies the liquid onto the        substrate to form the liquid immersion area;    -   a first liquid recovery mechanism which recovers the liquid from        a surface of the substrate; and    -   a second liquid recovery mechanism which has a recovery port        provided on the substrate stage and which recovers the liquid        after completion of the exposure for the substrate.

According to the present invention, the liquid in the liquid immersionarea on the substrate is recovered by not only the first liquid recoverymechanism but also the second liquid recovery mechanism having therecovery port on the stage after the completion of the liquid immersionexposure. Accordingly, it is possible to avoid the scattering and thefalling of the remaining liquid and the occurrence of the adhesion traceof the remaining liquid. Therefore, it is possible to form the desiredpattern accurately on the substrate.

According to a third aspect of the present invention, there is providedan exposure apparatus which exposes a substrate by projecting an imageof a pattern onto the substrate through a liquid; the exposure apparatuscomprising a projection optical system which projects the image of thepattern onto the substrate; and a detection unit which detects a stateof a surface of a part arranged in the vicinity of an image plane sideof the projection optical system.

According to the present invention, the detection unit can be used todetect the surface state of the part arranged in the vicinity of theimage plane of the projection optical system (whether or not any foreignmatter such as the liquid is adhered). Therefore, it is possible toperform an appropriate treatment including, for example, the removal ofthe foreign matter from the surface of the part by the washing,depending on an obtained result.

According to a fourth aspect of the present invention, there is provideda method for producing a device, wherein the exposure apparatus asdefined in any one of the aspects described above is used. According tothe present invention, it is possible to produce the device havingdesired performance in a state in which the environmental change and theoccurrence of the adhesion trace on the optical element disposed in thevicinity of the image plane of the projection optical system aresuppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic arrangement illustrating an embodiment of anexposure apparatus of the present invention.

FIG. 2 shows a schematic arrangement illustrating a liquid recoverymechanism and a liquid supply mechanism for forming a liquid immersionarea.

FIG. 3 shows a plan view illustrating a substrate stage.

FIG. 4 shows an example of a second liquid recovery unit.

FIGS. 5A and 5B show a schematic arrangement illustrating an example ofa first liquid-removing unit as a liquid-removing mechanism.

FIG. 6 shows a schematic arrangement illustrating an example of a firstliquid-removing unit as a liquid-removing mechanism.

FIG. 7 shows a schematic arrangement illustrating an example of a firstliquid-removing unit as a liquid-removing mechanism.

FIG. 8 shows a schematic arrangement illustrating an example of a secondliquid-removing unit as a liquid-removing mechanism.

FIG. 9 schematically illustrates a situation of movement of thesubstrate stage.

FIG. 10 shows a schematic arrangement illustrating an example of asecond liquid-removing unit as a liquid-removing mechanism.

FIG. 11 shows a schematic arrangement illustrating an example of asecond liquid-removing unit as a liquid-removing mechanism.

FIG. 12 shows a schematic arrangement illustrating an example of asecond liquid-removing unit as a liquid-removing mechanism.

FIG. 13 schematically shows an example of a washing mechanism.

FIG. 14 schematically shows an example of a washing mechanism.

FIG. 15 schematically shows an example of a foreign matter-detectingsystem.

FIG. 16 shows a plan view illustrating another embodiment of a substratestage.

FIG. 17 schematically shows an example of a first liquid-removing unit.

FIG. 18 schematically shows another embodiment of an exposure apparatusof the present invention.

FIG. 19 schematically shows another embodiment of the operation forremoving the liquid according to the present invention.

FIGS. 20A and 20B show the relationship between the gas nozzle and theoptical element.

FIG. 21 schematically shows another embodiment of an exposure apparatusof the present invention.

FIG. 22 schematically shows another embodiment of an exposure apparatusof the present invention.

FIG. 23 schematically shows another embodiment of an exposure apparatusof the present invention.

FIG. 24 schematically shows another embodiment of an exposure apparatusof the present invention.

FIG. 25 shows a plan view illustrating major parts of a substrate stageshown in FIG. 24 as viewed from an upper position.

FIG. 26 shows a flow chart illustrating exemplary steps of producing asemiconductor device.

FIG. 27 shows a flow chart illustrating an exemplary exposure procedurewith the exposure apparatus according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

An explanation will be made below about embodiments of the exposureapparatus according to the present invention with reference to thedrawings. However, the present invention is not limited thereto.

Embodiment of Exposure Apparatus Based on Use of First and SecondLiquid-Removing Units

FIG. 1 shows a schematic arrangement illustrating an embodiment of theexposure apparatus of the present invention. With reference to FIG. 1,an exposure apparatus EX includes a mask stage MST which supports a maskM, a substrate stage PST which supports a substrate P, an illuminationoptical system IL which illuminates, with an exposure light beam EL, themask M supported by the mask stage MST, a projection optical system PLwhich performs projection exposure for the substrate P supported by thesubstrate stage PST with an image of a pattern of the mask M illuminatedwith the exposure light beam EL, and a control unit CONT whichcollectively controls the overall operation of the exposure apparatusEX.

The exposure apparatus EX of this embodiment is a liquid immersionexposure apparatus to which the liquid immersion method is applied inorder that the exposure wavelength is substantially shortened to improvethe resolution and the depth of focus is substantially widened. Theexposure apparatus EX includes a liquid supply mechanism 10 whichsupplies the liquid 1 onto the substrate P, and a liquid recoverymechanism (first liquid recovery mechanism) 30 which recovers the liquid1 from the surface of the substrate P. In this embodiment, pure water isused as the liquid 1. The exposure apparatus EX forms a liquid immersionarea AR2 on at least a part of the substrate P including a projectionarea AR1 of the projection optical system PL by the liquid 1 suppliedfrom the liquid supply mechanism 10 at least during the period in whichthe pattern image of the mask M is transferred onto the substrate P.Specifically, the exposure apparatus EX is operated as follows. That is,the space between the surface (exposure surface) of the substrate P andthe optical element 2 disposed at the end portion of the projectionoptical system PL is filled with the liquid 1. The pattern image of themask M is projected onto the substrate P to expose the substrate Ptherewith via the projection optical system PL and the liquid 1 disposedbetween the projection optical system PL and the substrate P.

The embodiment of the present invention will now be explained asexemplified by a case of the use of the scanning type exposure apparatus(so-called scanning stepper) as the exposure apparatus EX in which thesubstrate P is exposed with the pattern formed on the mask M whilesynchronously moving the mask M and the substrate P in mutuallydifferent directions (opposite directions) in the scanning directions.In the following explanation, the X axis direction is the synchronousmovement direction (scanning direction) for the mask M and the substrateP in the horizontal plane, the Y axis direction (non-scanning direction)is the direction which is perpendicular to the X axis direction in thehorizontal plane, and the Z axis direction is the direction which isperpendicular to the X axis direction and the Y axis direction and whichis coincident with the optical axis AX of the projection optical systemPL. The directions about the X axis, the Y axis, and the Z axis aredesignated as θX, θY, and θZ directions respectively. The term“substrate” referred to herein includes substrates obtained by coating asemiconductor wafer surface with a resist, and the term “mask” includesa reticle formed with a device pattern to be subjected to the reductionprojection onto the substrate.

The illumination optical system IL is used so that the mask M, which issupported on the mask stage MST, is illuminated with the exposure lightbeam EL. The illumination optical system IL includes, for example, anexposure light source, an optical integrator which uniformizes theilluminance of the light flux radiated from the exposure light source, acondenser lens which collects the exposure light beam EL supplied fromthe optical integrator, a relay lens system, and a variable fielddiaphragm which sets the illumination area on the mask M illuminatedwith the exposure light beam EL to be slit-shaped. The predeterminedillumination area on the mask M is illuminated with the exposure lightbeam EL having a uniform illuminance distribution by the illuminationoptical system IL. Those usable as the exposure light beam EL radiatedfrom the illumination optical system IL include, for example, emissionlines (g-ray, h-ray, i-ray) in the ultraviolet region radiated, forexample, from a mercury lamp, far ultraviolet light beams (DUV lightbeams) such as the KrF excimer laser beam (wavelength: 248 nm), andvacuum ultraviolet light beams (VUV light beams) such as the ArF excimerlaser beam (wavelength: 193 nm) and the F₂ laser beam (wavelength: 157nm). In this embodiment, the ArF excimer laser beam is used. Asdescribed above, the liquid 1 is pure water in this embodiment, throughwhich the exposure light beam EL is transmissive even when the exposurelight beam EL is the ArF excimer laser beam. The emission line (g-ray,h-ray, i-ray) in the ultraviolet region and the far ultraviolet lightbeam (DUV light beam) such as the KrF excimer laser beam (wavelength:248 nm) are also transmissive through pure water.

The mask stage MST supports the mask M. The mask stage MST istwo-dimensionally movable in the plane perpendicular to the optical axisAX of the projection optical system PL, i.e., in the XY plane, and it isfinely rotatable in the θZ direction. The mask stage MST is driven by amask stage-driving unit MSTD such as a linear motor. The maskstage-driving unit MSTD is controlled by the control unit CONT. Amovement mirror 50 is provided on the mask stage MST. A laserinterferometer 51 is provided at a position opposed to the movementmirror 50. The position in the two-dimensional direction and the angleof rotation of the mask M on the mask stage MST are measured inreal-time by the laser interferometer 51. The result of the measurementis outputted to the control unit CONT. The control unit CONT drives themask stage-driving unit MSTD on the basis of the result of themeasurement obtained by the laser interferometer 51 to thereby positionthe mask M supported on the mask stage MST.

The projection optical system PL projects the pattern on the mask M ontothe substrate P at a predetermined projection magnification β to performthe exposure. The projection optical system PL includes a plurality ofoptical elements including the optical element (lens) 2 provided at theend portion on the side of the substrate P. The optical elements aresupported by a barrel PK. In this embodiment, the projection opticalsystem PL is the reduction system having the projection magnification βwhich is, for example, ¼ or ⅕. The projection optical system PL may beany one of the 1× magnification system and the magnifying system. Theoptical element 2, which is disposed at the end portion of theprojection optical system PL of this embodiment, is provided detachably(exchangeably) with respect to the barrel PK. The optical element 2,which is disposed at the end portion, is exposed (protrudes) from thebarrel PK. The liquid 1 in the liquid immersion area AR2 makes contactwith only the optical element 2. Accordingly, the barrel PK formed ofmetal can be prevented from any corrosion or the like.

The optical element 2 is formed of fluorite. Fluorite has a highaffinity for water. Therefore, the liquid 1 is successfully allowed tomake tight contact with the substantially entire surface of the liquidcontact surface 2 a of the optical element 2. That is, in thisembodiment, the liquid (pure water) 1, which has the high affinity forthe liquid contact surface 2 a of the optical element 2, is supplied.Therefore, the highly tight contact is effected between the liquid 1 andthe optical element 2. Quartz having a high affinity for water may beused as the optical element 2 as well. A water-attracting (lyophilic orliquid-attracting) treatment may be applied to the liquid contactsurface 2 a of the optical element 2 to further enhance the affinity forthe liquid 1.

The exposure apparatus EX further includes a focus-detecting system 4.The focus-detecting system 4 has a light-emitting section 4 a and alight-receiving section 4 b. The detecting light beam is projectedobliquely from an upper position onto the surface (exposure surface) ofthe substrate P via the liquid 1 from the light-emitting section 4 a.The reflected light beam from the surface of the substrate P is receivedby the light-receiving section 4 b. The control unit CONT controls theoperation of the focus-detecting system 4. Further, the position (focusposition) in the Z axis direction of the surface of the substrate P withrespect to a predetermined reference surface is detected on the basis ofa light-receiving result obtained by the light-receiving section 4 b.Respective focus positions at a plurality of respective points on thesurface of the substrate P are determined by using the focus-detectingsystem 4. Accordingly, it is also possible to detect the posture of thesubstrate P in an inclined direction. Those usable for the arrangementor the structure of the focus-detecting system 4 may include, forexample, one disclosed in Japanese Patent Application Laid-open No.8-37149.

The substrate stage PST supports the substrate P. The substrate stagePST includes a Z stage 52 which holds the substrate P by the aid of asubstrate holder, an XY stage 53 which supports the Z stage 52, and abase 54 which supports the XY stage 53. The substrate stage PST isdriven by a substrate stage-driving unit PSTD such as a linear motor.The substrate stage-driving unit PSTD is controlled by the control unitCONT. It goes without saying that the Z stage and the XY stage may beprovided as an integrated body. When the XY stage 53 of the substratestage PST is driven, the substrate P is subjected to the control of theposition in the XY directions (position in the direction substantiallyparallel to the image plane of the projection optical system PL).

A movement mirror 55, which is movable together with the substrate stagePST with respect to the projection optical system PL, is provided on thesubstrate stage PST (Z stage 52). A laser interferometer 56 is providedat a position opposed to the movement mirror 55. The angle of rotationand the position in the two-dimensional direction of the substrate P onthe substrate stage PST are measured in real-time by the laserinterferometer 56. The result of the measurement is outputted to thecontrol unit CONT. The control unit CONT drives the XY stage 53 by theaid of the substrate stage-driving unit PSTD on the basis of the resultof the measurement of the laser interferometer 56 to thereby positionthe substrate P supported on the substrate stage PST in the X axisdirection and the Y axis direction.

The control unit CONT drives the Z stage 52 of the substrate stage PSTby the aid of the substrate stage-driving unit PSTD. Accordingly, thecontrol unit CONT controls the position (focus position) in the Z axisdirection of the substrate P held by the Z stage 52 and the position inthe θX direction and the θY direction. That is, the Z stage 52 isoperated on the basis of the instruction from the control unit CONTbased on the result of the detection performed by the focus-detectingsystem 4. The focus position (Z position) and the angle of inclinationof the substrate P are controlled so that the surface (exposure surface)of the substrate P is adjusted to the image plane formed via theprojection optical system PL and the liquid 1.

An auxiliary plate 57 having a flat surface is provided on the substratestage PST (Z stage 52) so that the substrate P is surrounded thereby.The auxiliary plate 57 is installed so that the surface hasapproximately the same height as that of the surface of the substrate Pheld by the substrate holder. In this arrangement, a gap of about 0.1 to2 mm is formed between the auxiliary plate 57 and the edge of thesubstrate P. However, the liquid 1 scarcely flows into the gap owing tothe surface tension of the liquid 1. Even when the vicinity of thecircumferential edge of the substrate P is subjected to the exposure,the liquid 1 can be retained under the projection optical system PL bythe aid of the auxiliary plate 57.

A substrate alignment system 5, which detects the alignment mark on thesubstrate P or the reference mark provided on the Z stage 52, isprovided in the vicinity of the end portion of the projection opticalsystem PL. A mask alignment system 6, which detects the reference markprovided on the Z stage 52 via the mask M and the projection opticalsystem PL, is provided in the vicinity of the mask stage MST. Thoseusable for the arrangement of the substrate alignment system 5 include,for example, one disclosed in Japanese Patent Application Laid-open No.4-65603. Those usable for the arrangement of the mask alignment system 6include, for example, one disclosed in Japanese Patent ApplicationLaid-open No. 7-176468.

A first liquid-removing unit 40, which removes the liquid 1 remaining onthe reference member having the reference mark provided on the Z stage52, is provided in the vicinity of the substrate alignment system 5. Thesubstrate stage PST is provided with a second liquid recovery unit 20which recovers the liquid 1.

The liquid supply mechanism 10 supplies the predetermined liquid 1 ontothe substrate P in order to form the liquid immersion area AR2. Theliquid supply mechanism 10 includes a first liquid supply section 11 anda second liquid supply section 12 which are capable of feeding theliquid 1, a first supply nozzle 13 which is connected to the firstliquid supply section 11 through a supply tube 11A having a flow passageand which has a supply port for supplying the liquid 1 fed from thefirst liquid supply section 11 onto the substrate P, and a second supplynozzle 14 which is connected to the second liquid supply section 12through a supply tube 12A having a flow passage and which has a supplyport for supplying the liquid 1 fed from the second liquid supplysection 12 onto the substrate P. The first and second supply nozzles 13,14 make contact with the liquid 1 in the liquid immersion area AR2during the liquid immersion exposure. The first and second supplynozzles 13, 14 are arranged closely to the surface of the substrate P,and they are provided at mutually different positions in the surfacedirection of the substrate P. Specifically, the first supply nozzle 13of the liquid supply mechanism 10 is provided on one side (−X side) inthe scanning direction with respect to the projection area AR1. Thesecond supply nozzle 14 is provided on the other side (+X side) in thescanning direction so that the second supply nozzle 14 is opposed to thefirst supply nozzle 13.

Each of the first and second liquid supply sections 11, 12 includes, forexample, a tank for accommodating the liquid 1, and a pressurizing pump.The first and second liquid supply sections 11, 12 supply the liquid 1onto the substrate P through the supply tubes 11A, 12A and the supplynozzles 13, 14 respectively. The operation of the first and secondliquid supply sections 11, 12 for supplying the liquid is controlled bythe control unit CONT. The control unit CONT is capable of controllingthe liquid supply amounts per unit time onto the substrate P by thefirst and second liquid supply sections 11, 12 independentlyrespectively. Each of the first and second liquid supply sections 11, 12includes a temperature-adjusting mechanism for the liquid 1. The liquid1, which has approximately the same temperature of 23° C. as thetemperature in the chamber for accommodating the apparatus therein, issupplied onto the substrate P.

It is preferable that the pure water (liquid), which is supplied fromthe liquid supply sections 11, 12, has a transmittance of not less than99%/mm. In this case, it is desirable that the value of TOC (totalorganic carbon), which indicates the total amount of carbon contained inorganic compounds, is less than 3 ppb in relation to carbon compoundsdissolved in the pure water.

The liquid recovery mechanism (first liquid recovery unit) 30 recoversthe liquid 1 from the surface of the substrate P. The liquid recoverymechanism 30 includes first and second recovery nozzles 31, 32 each ofwhich has a recovery port arranged closely to the surface of thesubstrate P, and first and second liquid recovery sections 33, 34 whichare connected to the first and second recovery nozzles 31, 32 throughrecovery tubes 33A, 34A having flow passages respectively. The first andsecond recovery nozzles 31, 32 make contact with the liquid 1 in theliquid immersion area AR2 during the liquid immersion exposure. Each ofthe first and second liquid recovery sections 33, 34 includes, forexample, a sucking unit such as a vacuum pump, and a tank foraccommodating the recovered liquid 1. The first and second liquidrecovery sections 33, 34 recover the liquid 1 from the surface of thesubstrate P through the first and second recovery nozzles 31, 32 and therecovery tubes 33A, 34A. The operation of each of the first and secondliquid recovery sections 33, 34 for recovering the liquid is controlledby the control unit CONT. The control unit CONT is capable ofcontrolling the liquid recovery amounts per unit time by the first andsecond liquid recovery sections 33, 34 independently respectively.

FIG. 2 shows a plan view illustrating a schematic arrangement of theliquid supply mechanism 10 and the liquid recovery mechanism 30. Asshown in FIG. 2, the projection area AR1 of the projection opticalsystem PL is designed to have a slit shape (rectangular shape) in whichthe Y axis direction (non-scanning direction) is the longitudinaldirection. The liquid immersion area AR2, which is filled with theliquid 1, is formed on a part of the substrate P so that the projectionarea AR1 is included therein. As described above, the first supplynozzle 13 of the liquid supply mechanism 10, which is used to form theliquid immersion area AR2 for the projection area AR1, is provided onone side (−X side) in the scanning direction with respect to theprojection area AR1, and the second supply nozzle 14 is provided on theother side (+X side) in the scanning direction on the opposite side. Thefirst and second supply nozzles 13, 14 are formed to be linear as viewedin a plan view in which the Y axis direction is the longitudinaldirection respectively. The supply ports of the first and second supplynozzles 13, 14 are formed to be slit-shaped while the Y axis directionis the longitudinal direction respectively, and they are directed to thesurface of the substrate P. The liquid supply mechanism 10simultaneously supplies the liquid 1 from the ± sides in the X directionof the projection area AR1 from the supply ports of the first and secondsupply nozzles 13, 14.

As appreciated from FIG. 2, each of the first and second recoverynozzles 31, 32 of the liquid recovery mechanism 30 has a recovery portwhich is formed continuously to be circular arc-shaped so that therecovery port is directed to the surface of the substrate P. Asubstantially annular recovery port is formed by the first and secondrecovery nozzles 31, 32 which are arranged so that they are opposed toone another. The respective recovery ports of the first and secondrecovery nozzles 31, 32 are arranged to surround the projection area AR1and the first and second supply nozzles 13, 14 of the liquid supplymechanism 10. A plurality of partition members 35 are provided in therecovery port formed continuously to surround the projection area AR1.

The liquid 1, which is supplied onto the substrate P from the supplyports of the first and second supply nozzles 13, 14, is supplied so thatthe liquid 1 is spread while causing the wetting between the substrate Pand the lower end surface of the end portion (optical element 2) of theprojection optical system PL. The liquid 1, which is supplied from thefirst and second supply nozzles 13, 14, is recovered from the recoveryports of the first and second recovery nozzles 31, 32.

FIG. 3 shows a schematic plan view illustrating the Z stage 52 of thesubstrate stage PST as viewed from an upper position. The movementmirrors 55 are arranged on the mutually perpendicular two side surfacesof the rectangular Z stage 52. The substrate P is held at asubstantially central portion of the Z stage 52 by the aid of anunillustrated holder. As described above, the auxiliary plate 57, whichhas the flat surface of substantially the same height as that of thesurface of the substrate P, is provided around the substrate P. Aliquid-absorbing member 21, which constitutes a part of the secondliquid recovery unit 20 for recovering the liquid 1, is provided aroundthe auxiliary plate 57. The liquid-absorbing member 21 is an annularmember having a predetermined width, which is arranged in a groove(recovery port) 23 formed annularly on the Z stage 52. Theliquid-absorbing member 21 is formed of a porous material including, forexample, a porous ceramics. Alternatively, a sponge as a porous materialmay be used as the material for forming the liquid-absorbing member 21.When the liquid-absorbing member 21 formed of the porous material isused as described above, a predetermined amount of the liquid 1 can beretained by the liquid-absorbing member 21.

FIG. 4 shows a sectional view illustrating the second liquid recoveryunit 20. The second liquid recovery unit 20 includes theliquid-absorbing member 21 which is arranged in the groove (recoveryport) 23 formed annularly on the Z stage 52 as described above, a flowpassage 22 which is formed in the Z stage 52 and which is communicatedwith the groove 23, a tube passage 26 which is provided outside the Zstage 52 and which has one end connected to the flow passage 22, a tank27 which is connected to the other end of the tube passage 26 and whichis provided outside the Z stage 52, and a pump 29 as a sucking unitwhich is connected to the tank 27 via a valve 28. The liquid recoveryunit 20 drives the pump 29 to suck the liquid 1 recovered by theliquid-absorbing member 21 so that the liquid 1 is collected in the tank27. The tank 27 is provided with a discharge flow passage 27A. When apredetermined amount of the liquid 1 is pooled in the tank 27, theliquid 1 contained in the tank 27 is discharged to the outside via thedischarge flow passage 27A.

With reference to FIG. 3 again, a reference member 7 is provided in thevicinity of one corner of the Z stage 52. A reference mark PFM which isto be detected by the substrate alignment system 5 and a reference markMFM which is to be detected by the mask alignment system 6 are providedon the reference member 7 in a predetermined positional relationship.The surface of the reference member 7 is substantially flat, which alsofunctions as a reference surface for the focus-detecting system 4. Thereference surface for the focus-detecting system 4 may be provided onthe Z stage 52 separately from the reference member 7. The referencemember 7 and the auxiliary plate 57 may be provided as an integratedbody.

A liquid-absorbing member 42, which constitutes a part of the firstliquid-removing unit 40 for removing the liquid 1 remaining on thereference member 7, is provided in the vicinity of the reference member7 on the Z stage 52. Further, a second liquid-removing unit 60, whichremoves the liquid 1 remaining on the optical element 2 disposed at theend portion of the projection optical system PL and/or the barrel PKdisposed in the vicinity of the end portion, is provided in the vicinityof another corner of the Z stage 52.

Next, an explanation will be made with reference to a flow chart shownin FIG. 27 about a procedure for exposing the substrate P with thepattern on the mask M by using the exposure apparatus EX describedabove. The position information about the alignment mark is determinedin a state in which the liquid 1 is absent on the substrate P beforesupplying the liquid 1 from the liquid supply mechanism 10. The controlunit CONT moves the XY stage 53 while monitoring the output of the laserinterferometer 56 so that the portion corresponding to the optical axisAX of the projection optical system PL is advanced along a broken linearrow 43 shown in FIG. 3. During the movement, the substrate alignmentsystem 5 detects a plurality of alignment marks (not shown) formed onthe substrate P corresponding to the shot areas S1 to S11 withoutpassing through the liquid 1 (Step SA1, FIG. 27). The alignment marksare detected by the substrate alignment system 5 in a state in which theXY stage 53 is stopped. As a result, the position information about therespective alignment marks is determined in the coordinate systemprescribed by the laser interferometer 56. When the alignment marks aredetected by the substrate alignment system 5, all of the alignment markson the substrate P may be detected, or only a part thereof may bedetected.

Further, during the movement of the XY stage 53, the surface informationof the substrate P is detected by the focus-detecting system 4 withoutpassing through the liquid 1 (Step SA2, FIG. 27). The surfaceinformation is detected by the focus-detecting system 4 for all of theshot areas S1 to S11 on the substrate P respectively. The result of thedetection is stored in the control unit CONT while corresponding to theposition of the substrate P in the scanning direction (X axisdirection). The surface information may be detected by thefocus-detecting system 4 for only a part of the shot areas.

When the detection of the alignment mark of the substrate P and thedetection of the surface information of the substrate P are completed,the control unit CONT moves the XY stage 53 so that the detection areaof the substrate alignment system 5 is positioned on the referencemember 7. The substrate alignment system 5 detects the reference markPFM on the reference member 7 to determine the position information ofthe reference mark PFM in the coordinate system prescribed by the laserinterferometer 56 (Step SA3, FIG. 27).

As a result of the completion of the detection process for the referencemark PFM, the positional relationships between the reference mark PFMand the plurality of alignment marks on the substrate P, i.e., thepositional relationships between the reference mark PFM and theplurality of shot areas S1 to S11 on the substrate P are determinedrespectively. Further, the reference mark PFM and the reference mark MFMare in the predetermined positional relationship. Therefore, thepositional relationships between the reference mark MFM and theplurality of shot areas S1 to S11 on the substrate P in the XY plane aredetermined respectively.

The control unit CONT detects the surface information of the surface(reference surface) of the reference member 7 by using thefocus-detecting system 4 before or after the detection of the referencemark PFM by the substrate alignment system 5 (Step SA4, FIG. 27). Whenthe detection process for the surface of the reference member 7 iscompleted, the relationship between the surface of the reference member7 and the surface of the substrate P is determined.

Subsequently, the control unit CONT moves the XY stage 53 so that thereference mark MFM on the reference member 7 can be detected by the maskalignment system 6. In this situation, the end portion of the projectionoptical system PL is opposed to the reference member 7. The control unitCONT starts the supply and the recovery of the liquid 1 by the liquidsupply mechanism 10 and the liquid recovery mechanism 30, respectively.The space between the projection optical system PL and the referencemember 7 is filled with the liquid 1 to form the liquid immersion area.The size of the reference member 7 in the XY direction is sufficientlylarger than the sizes of the supply nozzles 13, 14 and the recoverynozzles 31, 32. The liquid immersion area AR2 is smoothly formed on thereference member 7.

Subsequently, the control unit CONT detects the reference mark MFM viathe mask M, the projection optical system PL, and the liquid 1 by usingthe mask alignment system 6 (Step SA5, FIG. 27). Accordingly, theposition of the mask M in the XY plane, i.e., the projection positioninformation of the image of the pattern of the mask M is detected byusing the reference mark MFM via the projection optical system PL andthe liquid 1.

When the detection process is completed as described above, the controlunit CONT stops the operation for supplying the liquid 1 onto thereference member 7 by the liquid supply mechanism 10. On the other hand,the control unit CONT continues, for a predetermined period of time, theoperation for recovering the liquid 1 from the surface of the referencemember 7 by the liquid recovery mechanism 30 (Step SA5.1). After thepredetermined period of time has elapsed, the control unit CONT stopsthe recovery operation having been performed by the liquid recoverymechanism 30. Further, in order to remove the liquid 1 which isunsuccessfully recovered by the liquid recovery mechanism 30 and whichremains on the reference member 7, the substrate stage PST is moved in adirection directed to a blow unit 41 of the first liquid-removing unit40 as described later on.

FIG. 5 shows such a situation that the liquid 1, which remains on thereference member 7 provided on the substrate stage PST (Z stage 52), isremoved by the first liquid-removing unit 40 which constitutes a part ofthe liquid-removing mechanism. FIG. 5A shows a schematic perspectiveview, and FIG. 5B shows a sectional view. With reference to FIG. 5, thefirst liquid-removing unit 40 includes the blow unit 41 which blows thegas against the reference member 7, and the liquid-absorbing member 42which is provided adjacently to the reference member 7. The blow unit 41includes a gas supply section 41A which is capable of feeding the gas,and a nozzle section 43 which is connected to the gas supply section41A. A blow port 43A of the nozzle section 43 is formed to beslit-shaped so that the blow port 43A is parallel to the in-planedirection of the surface of the reference member 7, which is arrangedclosely to the reference member 7. The liquid-absorbing member 42 isprovided at the position opposed to the blow port 43A of the nozzlesection 43 with the reference member 7 intervening therebetween. The gassupply section 41A and the nozzle section 43 are supported by anunillustrated support section which is provided independently from theprojection optical system PL. The liquid-absorbing member 42 is arrangedin a groove 44 as a recovery port provided in the Z stage 52. Theliquid-absorbing member 42 is formed of, for example, a porous materialsuch as a porous ceramics and a sponge, in the same manner as theliquid-absorbing member 21 of the second liquid recovery unit 20, whichis capable of retaining a predetermined amount of the liquid 1. The gasis fed from the gas supply section 41A, and thus the high speed gas isallowed to blow against the reference member 7 obliquely from an upperposition via the slit-shaped blow port 43A of the nozzle section 43. Thecontrol unit CONT allows the gas to blow against the reference member 7from the nozzle section 43 of the first liquid-removing unit 40.Accordingly, the liquid 1 remaining on the reference member 7 is blownoff and removed (Step SA5.2). In this procedure, the control unit CONTallows the gas to blow against the reference member 7 from the nozzlesection 43 while moving the substrate stage PST (i.e., the referencemember 7) with respect to the nozzle section 43 of the firstliquid-removing unit 40. Accordingly, the gas is blown uniformly againstthe entire surface of the reference member 7. The blown off liquid 1 isretained (recovered) by the liquid-absorbing member 42 which is arrangedat the position opposed to the blow port 43A of the nozzle section 43.

As shown in FIG. 5B, a flow passage 45, which is continued to the groove44, is formed in the Z stage 52. The bottom of the liquid-absorbingmember 42 arranged in the groove 44 is connected to the flow passage 45.The flow passage 45, which is connected to the groove 44 arranged withthe liquid-absorbing member 42, is connected to one end of a tubepassage 46 which is provided outside the Z stage 52. On the other hand,the other end of the tube passage 46 is connected to a pump 49 as asucking unit via a valve 48 and a tank 47 provided outside the Z stage52. The first liquid-removing unit 40 drives the gas supply section 41Aand drives the pump 49 so that the liquid 1 recovered by theliquid-absorbing member 42 is sucked to collect the liquid 1 in the tank47. The tank 47 is provided with a discharge flow passage 47A. When apredetermined amount of the liquid 1 is pooled in the tank 47, theliquid 1 contained in the tank 47 is discharged to the outside via thedischarge flow passage 47A.

Subsequently, the control unit CONT moves the XY stage 53 so that thesubstrate P is arranged under the projection optical system PL in orderto expose the respective shot areas S1 to S11 on the substrate P (StepSA6, FIG. 27). The control unit CONT drives the liquid supply mechanism10 to start the operation for supplying the liquid onto the substrate Pin the state in which the substrate P is arranged under the projectionoptical system PL. The liquid 1, which is fed from the first and secondliquid supply sections 11, 12 of the liquid supply mechanism 10respectively in order to form the liquid immersion area AR2, flowsthrough the supply tubes 11A, 12A, and then the liquid 1 is suppliedonto the substrate P via the first and second supply nozzles 13, 14 toform the liquid immersion area AR2 between the projection optical systemPL and the substrate P. In this situation, the supply ports of the firstand second supply nozzles 13, 14 are arranged on the both sides in the Xaxis direction (scanning direction) of the projection area AR1. Thecontrol unit CONT simultaneously supplies the liquid 1 onto thesubstrate P on the both sides of the projection area AR1 from the supplyports of the liquid supply mechanism 10. Accordingly, the liquid 1,which is supplied onto the substrate P, forms, on the substrate P, theliquid immersion area AR2 in a range wider than at least the projectionarea AR1. Further, the control unit CONT controls the first and secondliquid recovery sections 33, 34 of the liquid recovery mechanism 30 toperform the operation for recovering the liquid from the surface of thesubstrate P concurrently with the operation for supplying the liquid 1performed by the liquid supply mechanism 10. In other words, the controlunit CONT simultaneously performs the liquid supply by the liquid supplymechanism 10 and the liquid recovery by the liquid recovery mechanism(first liquid recovery mechanism) 30 in order to form the liquidimmersion area AR2 during the exposure for the substrate P (Step SA7,FIG. 27). Accordingly, the liquid 1 on the substrate P, which flows tothe outside of the projection area AR1 from the supply ports of thefirst and second supply nozzles 13, 14, is recovered by the recoveryports of the first and second recovery nozzles 31, 32. As describedabove, the liquid recovery mechanism 30 recovers the liquid 1 from thesurface of the substrate P through the recovery ports provided tosurround the projection area AR1.

The respective shot areas S1 to S11 on the substrate P are subjected tothe scanning exposure by using the respective pieces of informationdetermined during the detection process as described above (Step SA8,FIG. 27). That is, the respective shot areas S1 to S11 on the substrateP and the mask M are subjected to the positional adjustment during thescanning exposure for the respective shot areas respectively on thebasis of the information about the positional relationships between thereference mark PFM and the respective shot areas S1 to S11 determinedbefore the supply of the liquid 1, and the information about theprojection position of the image of the pattern of the mask M determinedby using the reference mark MFM after the supply of the liquid 1.

The positional relationship is adjusted between the surface of thesubstrate P and the image plane formed via the liquid 1 during thescanning exposure for the respective shot areas S1 to S11 on the basisof the surface information of the substrate P determined before thesupply of the liquid 1 and the surface information of the surface of thesubstrate P detected by using the focus-detecting system 4 during thescanning exposure.

In this embodiment, when the liquid 1 is supplied to the substrate Pfrom the both sides of the projection area AR1 in the scanningdirection, the control unit CONT controls the liquid supply operation ofthe first and second liquid supply sections 11, 12 of the liquid supplymechanism 10 so that the liquid supply amount per unit time, which is tobe supplied in front of the projection area AR1 in relation to thescanning direction, is set to be larger than the liquid supply amount tobe supplied on the side opposite thereto. For example, when the exposureprocess is performed while moving the substrate P in the +X direction,the control unit CONT is operated so that the liquid amount from the −Xside with respect to the projection area AR1 (i.e., from the firstsupply nozzle 13) is made larger than the liquid amount from the +X side(i.e., from the second supply nozzle 14). On the other hand, when theexposure process is performed while moving the substrate P in the −Xdirection, the liquid amount from the +X side with respect to theprojection area AR1 is made larger than the liquid amount from the −Xside.

When the scanning exposure is completed for the respective shot areas S1to S11 on the substrate P, then the control unit CONT stops the supplyof the liquid by the liquid supply mechanism 10, and the substrate stagePST is moved so that the recovery port 23 of the second liquid recoveryunit 20 provided for the substrate stage PST is opposed to theprojection optical system PL. The control unit CONT uses, incombination, the liquid recovery mechanism (first liquid recoverymechanism) 30 and the second liquid recovery unit 20 to recover theliquid 1 existing under the projection optical system PL (Step SA9). Inthis manner, the liquid 1 of the liquid immersion area AR2 is recoveredsimultaneously by using the liquid recovery mechanism (first liquidrecovery unit) 30 having the recovery port arranged over the substratestage PST and the second liquid recovery unit 20 having the recoveryport arranged on the substrate stage PST. Therefore, it is possible tosuppress the liquid 1 from remaining on the substrate P and the endportion of the projection optical system PL.

The second liquid recovery unit 20 recovers the liquid 1 of the liquidimmersion area AR2 after the completion of the exposure for thesubstrate P. However, the liquid 1, which outflows to the outside of thesubstrate P (auxiliary plate 57), may be recovered during the liquidimmersion exposure. The recovery port 23 of the second liquid recoveryunit 20 is provided in the zonal (annular) form around the substrate P.However, the recovery port 23 may be provided partially at apredetermined position in the vicinity of the substrate P (auxiliaryplate 57) considering the movement direction of the substrate stage PSTafter the completion of the exposure for the substrate P. The liquidimmersion exposure itself is not affected even when the vibration, whichis accompanied by the recovery operation, is increased before and afterthe liquid immersion exposure. Therefore, in this period, the recoverypower of the liquid recovery mechanism 30 may be increased as comparedwith the power brought about during the liquid immersion exposure.

When the liquid 1 on the substrate P is unsuccessfully recovered afterthe completion of the liquid immersion exposure, the substrate P may bedealt with as follows, although the substrate P is not a part. That is,for examples the substrate stage PST, which supports the substrate P, ismoved to arrange the substrate P at a position separated from theprojection optical system PL, specifically at a position under the blowunit 41 of the first liquid-removing unit 40. The gas is blown againstthe substrate P to remove the liquid. The blown off liquid 1 can becollected in the tank 47 by effecting the suction with the pump 42 bythe aid of the liquid-absorbing member. Alternatively, the blown offliquid 1 may be recovered by the second liquid recovery unit 20. Ofcourse, the gas blow operation can be performed not only for thesubstrate P but also for the surfaces of the auxiliary plate 57 and theZ stage 52 disposed outside the auxiliary plate 57.

As described above, the first liquid recovery unit 40 removes the liquid1 remaining on the reference member 7. However, it is also possible toremove the liquid 1 remaining on any part (area) other than thereference member 7 on the substrate stage PST. For example, when theliquid 1 is subjected to the outflow and/or the scattering to theoutside of the substrate P during the liquid immersion exposure, and theliquid 1 is adhered onto the substrate stage PST (Z stage 52), then theliquid 1 on the substrate stage PST can be recovered by the firstliquid-removing unit 40 after the completion of the exposure for thesubstrate P. In this case, the liquid 1, which has been blown off by theblow unit 41 of the first liquid-removing unit 40, may be recovered bythe liquid-absorbing member 21 arranged in the groove (recovery port) 23of the second liquid recovery unit 20.

The nozzle section 43 of the blow unit 41 may be previously providedmovably with respect to the substrate stage PST. The liquid 1, which hasflown out to the outside of the substrate P, may be recovered during theexposure and/or after the completion of the exposure for the substrateP.

As explained above, the first liquid-removing unit 40 is provided, whichremoves the liquid 1 remaining on the reference member 7 provided on thesubstrate stage PST (Z stage 52). Therefore, it is possible to preventthe liquid 1 from remaining on the reference member 7. Further, theliquid 1 is recovered by using the recovery port on the substrate stagePST as well after the completion of the exposure for the substrate P.Therefore, it is possible to prevent the liquid 1 from remaining on thesubstrate P and/or at the end portions of the nozzle and the projectionoptical system PL, and it is possible to prevent the liquid 1 fromfalling and scattering to the substrate or the like. In the embodimentdescribed above, the first liquid-removing unit 40 has theliquid-absorbing member 42 arranged in the vicinity of the referencemember 7. However, the liquid-absorbing member 42 may be omitted. Inthis case, the liquid 1, which has been removed from the surface of thereference member 7, may be allowed to remain in a predetermined area onthe substrate stage PST at which the exposure operation and themeasuring operation are not affected thereby as well.

FIG. 6 shows another embodiment of the first liquid-removing unit 40. Inthe following description, the same or equivalent constitutive portionsas those of the embodiment described above will be designated by thesame reference numerals, any explanation of which will be simplified oromitted. With reference to FIG. 6, the first liquid-removing unit 40 isprovided with a sucking unit 81 which sucks the liquid 1 adhered ontothe reference member 7. The sucking unit 81 is arranged at a positionopposed to the blow unit 41 to interpose the reference member 7therebetween. The sucking unit 81 includes a sucking section 81A whichincludes a tank and a pump, and a sucking nozzle 82 which is connectedto the sucking section 81A. A sucking port 82A of the sucking nozzle 82is arranged closely to the reference member 7. When the liquid 1remaining on the reference member 7 is removed, then the blow unit 41blows the gas against the reference member 7, and the sucking unit 81sucks the liquid 1 from the surface of the reference member 7.

In the illustrative embodiment explained with reference to FIG. 6, thefirst liquid-removing unit 40 is provided with both of the blow unit 41and the sucking unit 81. However, it is also allowable to adopt anarrangement in which only the sucking unit 81 is provided. The suckingunit 81 sucks the liquid 1 remaining on the reference member 7 from thesucking port 82A, and thus the liquid 1 can be removed (recovered). Thenozzle section 82 of the sucking unit 81 may be provided movably withrespect to the substrate stage PST to recover the liquid 1 flown out tothe outside of the substrate P during the exposure and/or after thecompletion of the exposure for the substrate P. In the embodiment shownin FIG. 6, the first liquid-removing unit 40 has the liquid-absorbingmember 42 arranged in the vicinity of the reference member 7. However,the liquid-absorbing member 42 may be omitted.

FIG. 7 shows a sectional view illustrating still another embodiment ofthe first liquid-removing unit 40. As shown in FIG. 7, the firstliquid-removing unit 40 includes a cover member 84 which covers thereference member 7, and a dry gas supply section 85 which supplies thedry gas to the internal space of the cover member 84. The dry gas supplysection 85 supplies the dry gas to the internal space of the covermember 84 arranged over the reference member 7 via a tube passage 86.Accordingly, the vaporization of the liquid 1 remaining on the referencemember 7 is facilitated, and thus the liquid 1 is removed. The firstliquid-removing unit 40 removes the liquid on the part such as thereference member 7 carried on the substrate stage PST. However, when theexposure apparatus EX carries a stage provided with a reference sectionand/or a measuring member separately from the substrate stage PST asdisclosed in Japanese Patent Application Laid-open No. 11-135400, theliquid on the part on the stage can be also removed.

Next, an explanation will be made with reference to FIG. 8 about thesecond liquid-removing unit 60 for removing the liquid 1 or the likeremaining on the barrel PK disposed in the vicinity of the end portionand/or the optical element 2 disposed at the end portion of theprojection optical system PL. With reference to FIG. 8, the secondliquid-removing unit 60 includes a blow unit 61 which blows the gasagainst the optical element 2 for constructing the part disposed at theend portion of the projection optical system PL and the barrel PKdisposed in the vicinity thereof, and a recovery unit (sucking unit) 62which recovers the fallen liquid blown off by the gas blow effected bythe blow unit 61. The blow unit 61 includes a gas supply section 63, anda nozzle section 64 which is connected to the gas supply section 63 andwhich is provided in a recess 64B of the Z stage 52. The nozzle section64 has a blow port 64A which is directed upwardly and which is capableof being arranged in the vicinity of the end portion of the projectionoptical system PL. On the other hand, the recovery unit 62 includes arecovery port (groove) 65 which is provided in the Z stage 52, aliquid-absorbing member 66 which is formed of a porous material arrangedin the recovery port 65, a flow passage 67 which is arranged in the Zstage 52 and which is communicated with the groove 66, a tube passage 68which is provided outside the Z stage 52 and which has one end connectedto the flow passage 67, a tank 69 which is connected to the other end ofthe tube passage 68 and which is provided outside the Z stage 52, and apump 71 as a sucking unit which is connected to the tank 69 via a valve70. The recovery unit 62 drives the pump 71 to suck the liquid 1recovered by the liquid-absorbing member 66 so that the liquid 1 iscollected in the tank 69. The tank 69 is provided with a discharge flowpassage 69A. When a predetermined amount of the liquid 1 is pooled inthe tank 69, the liquid 1 contained in the tank 69 is discharged to theoutside via the discharge flow passage 69A.

In this embodiment, the blow port 64A of the nozzle section 64 of theblow unit 61 is slit-shaped, in which the Y axis direction is thelongitudinal direction (see FIG. 3). The recovery port 65 of therecovery unit 62 is formed to have a rectangular shape in which the Yaxis direction is the longitudinal direction at the position adjoiningon the +X side of the blow port 64A. The second liquid-removing unit 60removes the liquid 1 remaining on the end portion of the projectionoptical system PL allowed to make contact with the liquid 1 in theliquid immersion area AR2 during the exposure for the substrate P aswell as on the supply nozzles (parts) 13, 14 of the liquid supplymechanism 10 and the recovery nozzles (parts) 31, 32 of the liquidrecovery mechanism 30 after the completion of the exposure for thesubstrate P. Of course, it is also possible to remove the liquid fromonly the end portion of the projection optical system PL or from onlythe nozzles.

As described above, the control unit CONT recovers the liquid 1 from thesurface of the substrate P (Step SA9, FIG. 27) by using the liquidrecovery mechanism (first liquid recovery unit) 30 after the completionof the liquid immersion exposure for the substrate P (after thecompletion of Step SA8). After the completion of the recovery of theliquid 1 from the surface of the substrate P by the liquid recoverymechanism 30, the control unit CONT moves the substrate stage PST sothat the second liquid-removing unit 60 is arranged under the projectionoptical system PL. The second liquid-removing unit 60 allows the gas toblow from the nozzle section 64 of the blow unit 61 arranged obliquelydownwardly with respect to the end portion of the projection opticalsystem PL. The liquid 1, which remains on the end portion of theprojection optical system PL, is blown off and removed (Step SA10, FIG.27). The blown off liquid 1 falls onto the liquid-absorbing member 66disposed adjacently to the nozzle section 64. The liquid 1 is recoveredby the recovery port 65 arranged with the liquid-absorbing member 66 ofthe recovery unit 62. In this embodiment, the control unit CONT drivesthe second liquid-removing unit 60 while moving the substrate stage PST,for example, in the X axis direction perpendicular to the longitudinaldirection (Y axis direction) of the recovery port 65 and the blow port64A. Accordingly, the gas is allowed to blow against the end portion ofthe projection optical system PL as a matter of course, as well asagainst the recovery nozzles 31, 32 of the liquid recovery mechanism 30and the supply nozzles 13, 14 of the liquid supply mechanism 10 disposedtherearound. It is possible to remove the liquid 1 remaining on thesupply nozzles 13, 14 and the recovery nozzles 31, 32 as well.

As explained above, the liquid 1, which remains on the end portion ofthe projection optical system PL allowed to make contact with the liquid1 in the liquid immersion area AR2 during the exposure as well as on thesupply nozzles 13, 14 and the recovery nozzles 31, 32, is removed.Accordingly, as schematically shown in FIG. 9, even when the substratestage PST is moved from the position under the projection optical systemPL (exposure process position A) to the position (load/unload positionB) at which the substrate P is loaded and/or unloaded, it is possible tosuppress the occurrence of any inconvenience which would be otherwisecaused such that the liquid 1, which remains, for example, on the endportion of the projection optical system PL, falls to affect thesurrounding equipment and brings about the environmental change. Inparticular, it is possible to suppress the occurrence of the adhesiontrace (water mark) by preventing the liquid 1 from remaining on theoptical element 2 disposed at the end portion of the projection opticalsystem PL.

Further, the second liquid-removing unit 60 is provided for thesubstrate stage PST. Accordingly, when the second liquid-removing unit60 is driven while moving the substrate stage PST, the gas can beallowed to blow against the projection optical system PL, the supplynozzles, and the recovery nozzles while scanning the secondliquid-removing unit 60, even when any actuator is not provided.Further, for example, as shown in FIG. 9, the operation for blowing thegas is performed by the second liquid-removing unit 60 during the periodof the movement from the exposure process position A to the load/unloadposition B after the completion of the liquid immersion exposure.Accordingly, it is possible to simultaneously perform theliquid-removing operation (gas-blowing operation) and the stage-movingoperation. It is possible to improve the time efficiency of the seriesof the exposure process. Therefore, it is preferable that the secondliquid-removing unit 60 is previously provided at the position to passunder the projection optical system PL during the movement of thesubstrate stage PST from the exposure process position A to theload/unload position B.

FIGS. 10 and 11 show modified embodiments of the second liquid-removingunit 60. As shown in FIG. 10, a large groove 72 is formed on the Z stage52 beforehand. The nozzle section 64 of the blow unit 61 and the flowpassage (recovery port) 67 of the recovery unit 62 may be arranged inthe groove 72. In the illustrative embodiment shown in FIG. 10, theliquid-absorbing member 66 is not provided. As described above, it isalso possible to adopt the arrangement in which the liquid-absorbingmember 66 is not provided. Alternatively, as shown in FIG. 11, aplurality of nozzle sections 64 (two nozzle sections 64, in theillustrative embodiment shown in FIG. 11) of the blow unit 61 may beprovided in the groove. Further, as exemplified in the illustrativeembodiments shown in FIGS. 10 and 11, the groove 72, which is largerthan the size (width) of the end portion of the projection opticalsystem PL, is provided, and the nozzle section 64 and the recovery port67 are arranged in the groove 72. Accordingly, all of the liquid 1,which falls as a result of the blow of the gas, can be recovered by thegroove 72. Therefore, it is possible to suppress the scattering of theliquid 1 to the surroundings.

Alternatively, as shown in FIG. 12, a cover member 73, which preventsthe liquid 1 subjected to the gas blow from being scattered to thesurroundings, can be provided around the recovery port 65 and the blowport 64A of the nozzle section 64. The cover member 73 shown in FIG. 12is formed to be U-shaped as viewed in a plan view so that the covermember 73 can be arranged to surround the end portion of the projectionoptical system PL. The cover member 73 is formed so that the blow port64A of the nozzle section 64 is arranged on the side of the opening ofthe U-shaped form. Further, the cover member 73 is formed so that theside of the opening of the U-shaped form of the cover member 73 facesthe movement direction of the substrate stage PST (X axis direction).The end portion of the projection optical system PL enters and existsthe inside of the cover member 73 on the side of the opening of theU-shaped form. The blow port 64A and the recovery port 65, for each ofwhich the Y axis direction is the longitudinal direction, are providedinside the cover member 73. Accordingly, the liquid can be efficientlyremoved, for example, from the end portion of the projection opticalsystem PL while avoiding the scattering of the liquid 1 by one time ofthe scanning movement of the substrate stage PST.

The liquid 1, which outflows to the outside of the substrate P, can bealso recovered during the exposure for the substrate P by the aid of therecovery port 65 of the recovery unit 62 of the second liquid-removingunit 60. In this arrangement, it is preferable that a plurality ofrecovery ports 65 of the recovery unit 62 are provided at predeterminedintervals around the substrate P.

In the embodiments shown in FIGS. 8 to 12, the second liquid-removingunit 60 is provided with the recovery unit 62 in the vicinity of thenozzle section 64. However, the recovery unit 62 may be omitted. In thisarrangement, the liquid 1, which is removed from the end portion of theprojection optical system PL, can be also allowed to remain in apredetermined area on the substrate stage PST in which no influence isexerted on the exposure operation and the measuring operation.

In the embodiments shown in FIGS. 8 to 12, the second liquid-removingunit 60 is arranged on the substrate stage PST. However, the secondliquid-removing unit 60 may be arranged on a portion or a memberdifferent from the substrate stage PST. For example, a stage, which ismovable on the side of the image plane of the projection optical systemPL, may be further provided independently from the substrate stage PST,and the second liquid-removing unit 60 may be arranged on the stage.

A sucking port may be provided in the vicinity of the projection opticalsystem PL, the supply nozzle, the recovery nozzle, and/or the blow port64A of the nozzle section 64 of the second liquid-removing unit 60.Alternatively, a sucking port may be provided in place of the blow port64A to recover the liquid adhered to the forward end surface of theprojection optical system PL, the supply nozzle, and/or the recoverynozzle.

Even when the liquid 1 is removed from the end portion of the projectionoptical system PL, then impurities and/or foreign matters, which arecontained in the liquid 1, may adhere to the optical element 2 disposedat the end portion of the projection optical system PL, and the opticalelement 2 may be contaminated therewith in some cases. The impuritiesand/or foreign matters herein include, for example, broken pieces of thephotoresist and deposits of the electrolyte contained in thephotoresist. Accordingly, it is preferable to wash the optical element 2before or after removing (blowing off or sucking) the liquid 1 remainingon the optical element 2 disposed at the end portion of the projectionoptical system PL.

FIG. 13 schematically shows a state in which the end portion of theprojection optical system PL is washed. In an embodiment shown in FIG.13, a washing station 90 is provided at a position different from thatof the substrate P held by the substrate holder, on the substrate stagePST (Z stage 52). A washing plate 91 is provided for the washing station90. The washing plate 91 is, for example, a plate member havingsubstantially the same size as that of the substrate P.

In order to wash the optical element 2 disposed at the end portion ofthe projection optical system PL after (or before) the completion of theliquid immersion exposure, the control unit CONT moves the substratestage PST to arrange the washing plate 91 (washing station 90) under theprojection optical system PL. The control unit CONT drives the liquidsupply mechanism 10 and the liquid recovery mechanism 30 to form theliquid immersion area AR2 between the projection optical system PL andthe washing plate 91. The optical element 2, which is disposed at theend portion of the projection optical system PL, is washed with theliquid 1 in the liquid immersion area AR2 formed on the washing plate91. After the washing process comes to an end, the secondliquid-removing unit 60 is used as described above to remove the liquid1 remaining on the optical element 2 disposed at the end portion of theprojection optical system PL.

In the case of the washing station 90 shown in FIG. 13, the liquidsupply mechanism 10 and the liquid recovery mechanism 30 are used toform the liquid immersion area AR2 on the washing plate 91, and theoptical element 2 disposed at the end portion of the projection opticalsystem PL is washed with the liquid 1 in the liquid recovery amount AR2.However, as shown in FIG. 14, a washing mechanism 95 may be provided forthe washing station 90, and the washing mechanism 95 can be used to washthe optical element 2 disposed at the end portion of the projectionoptical system PL. The washing mechanism 95 of the washing station 90shown in FIG. 14 includes a washing liquid supply section 96, a jettingsection 97 which is connected to the washing liquid supply section 96and which has a jetting port 97A for jetting or spouting the washingliquid fed from the washing liquid supply section 96 to the opticalelement 2 disposed at the end portion of the projection optical systemPL, a recovery tube 98 which has a recovery port 98A for recovering thewaste liquid after washing the optical element 2, and a recovery section99 which is connected to the recovery tube 98 and which includes, forexample, a pump and a tank. The jetting port 97A and the recovery port98A are arranged in a groove 94 formed on the substrate stage PST (Zstage 52). After the completion of the liquid immersion exposure, thewashing station 90 is arranged under the projection optical system PL,and the washing liquid is jetted or spouted toward the optical element 2disposed at the end portion of the projection optical system PL by usingthe jetting section 97 of the washing mechanism 95. Accordingly, theoptical element 2 is washed. In this arrangement, the washing liquid isprevented from the scattering to the surroundings by arranging thejetting port 97A and the recovery port 98A in the groove 94.

The washing station 90 (washing plate 91) is arranged on the substratestage PST. However, the washing station 90 (washing plate 91) may bearranged on a member different from the substrate stage PST. Forexample, a stage, which is movable on the side of the image plane of theprojection optical system PL, may be further provided independently fromthe substrate stage PST, and the washing station may be arranged on thestage.

It is preferable to confirm whether or not any foreign matter is adheredto the optical element 2 disposed at the end portion of the projectionoptical system PL by using a foreign matter-detecting system after thewashing operation and the liquid removal operation. FIG. 15schematically shows an example of the foreign matter-detecting system100. The foreign matter referred to herein includes the remaining liquid(liquid droplet) 1, for example, as well as the broken pieces of thephotoresist and the deposits of the electrolyte contained in thephotoresist as described above.

With reference to FIG. 15, the foreign matter-detecting system 100includes a light-emitting section 118 which is provided on the substratestage PST (Z stage 52) and which radiates a predetermined radiationlight beam from an obliquely downward position onto the surface of theoptical element 2 disposed at the end portion of the projection opticalsystem PL, a branching mirror 119 which is arranged on the optical pathfor connecting the surface of the optical element 2 and thelight-emitting section 118, a first light-receiving section 120 which isprovided on the substrate stage PST and which receives the reflectedlight beam from the surface of the optical element 2 on the basis of theradiation from the light-emitting section 118, and a secondlight-receiving section 121 which is arranged at a position over thesubstrate stage PST and which receives the branched light beam from thebranching mirror 119 on the basis of the radiation from thelight-emitting section 118. In this embodiment, for example, thelight-emitting section 118 and the first light-receiving section 120,which constitute the foreign matter-detecting system 100, are providedat the positions other than those of the substrate holder and thewashing station on the substrate stage PST. The light-receiving resultsobtained by the first and second light-receiving sections 120, 121 areoutputted as photoelectric signals to the control unit CONT whichconstitutes a part of the foreign matter-detecting system 100. Thecontrol unit CONT is constructed to calculate, as the real reflectance,the light reflectance of the surface of the optical element 2 on thebasis of the photoelectric signals outputted from the first and secondlight-receiving sections 120, 121 so that the degree of contamination ofthe surface of the optical element 2 is measured on the basis of theresult of comparison between the calculated real reflectance and thepreviously stored predetermined reflectance. In other words, if anyforeign matter adheres to the optical element 2, then any scatteredlight is generated due to the foreign matter to change the reflectance,and the receiving amount of light received by the first light-receivingsection 120 is changed. The control unit CONT previously stores, as thepredetermined reflectance, the light reflectance of the surface of theoptical element 2 measured upon the completion of the production of thisapparatus in which it is assumed that the surface of the optical element2 is not contaminated to such an extent that the optical characteristicsare affected.

As explained with reference to FIGS. 13 and 14, the control unit CONTmoves the substrate stage PST to arrange the foreign matter-detectingsystem 100 under the projection optical system PL after completing thewashing process for the optical element 2 disposed at the end portion ofthe projection optical system PL. When the predetermined radiation lightbeam is radiated from the light-emitting section 118, then the radiationlight beam, which is transmitted through the branching mirror 119, isradiated onto the surface of the optical element 2, and the radiationlight beam is reflected by the surface. The reflected light beam isreceived by the first light-receiving section 120. On the other hand,the radiation light beam (branched light beam), which is branched by thebranching mirror 119, does not arrive at the surface of the opticalelement 2, and the radiation light beam is received by the secondlight-receiving section 121. The photoelectric signals, each of which issubjected to the photoelectric conversion by one of the light-receivingsections 120, 121, are outputted to the control unit CONT respectively.The control unit CONT calculates the reflectance of the surface of theoptical element 2 on the basis of the photoelectric signal supplied fromthe first light-receiving section 120 and the photoelectric signalsupplied from the second light-receiving section 121. That is, ingeneral, when the light beam comes, at a certain angle of incidence,into the boundary surface between two media, the reflectance R isrepresented by R=Ir/I₀ provided that I₀ represents the intensity of theenergy of the incoming light flux, and Ir represents the intensity ofthe energy of the reflecting light flux. Therefore, the control unitCONT determines the real reflectance Rr assuming that the intensity ofthe energy based on the photoelectric signal from the firstlight-receiving section 120 is Ir, and the intensity of the energy basedon the photoelectric signal from the second light-receiving section 121is I₀. Subsequently, the control unit CONT reads the predeterminedreflectance R₀ which is previously stored in order to calculate thedifference ΔR (=R₀−Rr) between the predetermined reflectance R₀ and thereal reflectance Rr. The display signal, which is based on thedetermined difference ΔR between the both reflectances R₀ and Rr, isoutputted to the display unit 126. The display unit 126 numericallydisplays the degree of contamination of the surface of the opticalelement 2 on the basis of the display signal. If the degree ofcontamination exceeds a predetermined allowable value, then the controlunit CONT judges that the foreign matter is present in an amount of notless than an allowable amount on the surface of the optical element 2,and the control unit CONT controls the washing unit so that the washingprocess is performed again.

This embodiment is constructed such that the radiation light beam isradiated onto the optical element 2, and the scattered light on thesurface of the optical element 2 is detected. However, when any foreignmatter adheres to the optical element 2, the uneven illuminance or thetelecentric deviation is observed on the side of the image plane of theprojection optical system PL. Therefore, it is possible to detectwhether or not any foreign matter adheres by measuring the illuminanceat the focus plane and the defocus plane respectively by using anilluminance sensor provided on the substrate stage PST.

In the embodiment shown in FIG. 15, the liquid and the foreign matter(impurity) adhered to the surface of the optical element 2 are detectedby radiating the light beam onto the optical element 2 and receiving thescattered light therefrom. However, the detecting method is not limitedthereto. For example, the detection may be performed by using the maskalignment system 6 described above. Further, the foreignmatter-detecting system may be used to confirm whether or not anyforeign matter adheres to the optical element 2 disposed at the endportion of the projection optical system PL not only after the washingof the surface of the optical element 2 but also at a predeterminedtiming during the exchange of the substrate P or the like. When anyforeign matter is detected, the washing operation may be performed. Theforeign matter-detecting system 100 detects the foreign matter on theoptical element 2 disposed at the end portion of the projection opticalsystem PL. However, it is also allowable to detect the foreign matter onthe surface of any other part to make contact with the liquid on theside of the image plane of the projection optical system PL.

Another Embodiment of Exposure Apparatus Based on Use of FirstLiquid-Removing Unit

FIG. 16 shows another embodiment of the exposure apparatus provided withthe first liquid-removing unit. In this embodiment, the Z stage 52 isprovided with a plate member (upper plate) 138A which constitutes a partof an uneven illuminance sensor (measuring system) 138 for receiving thelight beam radiated onto the side of the image plane (side of thesubstrate P) via the projection optical system PL, and aliquid-absorbing member 142, which recovers the liquid removed from theplate member 138A, is further provided in the vicinity thereof. Theliquid-absorbing member 142 is arranged in a groove 144 formed in the Zstage 52. The plate member 138A is formed such that the surface of theglass plate is subjected to the patterning with a thin film including alight-shielding material such as chromium, and a pinhole 138P isprovided at a central portion thereof. The upper surface of the platemember 138A has the liquid repellence. In this embodiment, the surfaceof the plate member 138A is coated with a material having the liquidrepellence such as a fluorine-based compound.

FIG. 17 shows a situation in which the adhered liquid is removed fromthe plate member 138A which is provided on the substrate stage PST andwhich constitutes a part of the uneven illuminance sensor 138. In thisembodiment, the uneven illuminance sensor 138 measures, at a pluralityof positions, the illuminance (intensity) of the exposure light beamradiated onto the side of the image plane by the aid of the projectionoptical system PL to measure the uneven illuminance (illuminancedistribution) of the exposure light beam radiated onto the side of theimage plane of the projection optical system PL, as disclosed inJapanese Patent Application Laid-open No. 57-117238 (corresponding toU.S. Pat. No. 4,465,368). The uneven illuminance sensor 138 includes theplate member 138A which is provided on the substrate stage PST (Z stage52), which has the light-shielding film subjected to the patterning onthe surface of the glass plate, and which has the pinhole 138P formed atthe central portion thereof, an optical system 138C which is embedded inthe Z stage 52 and which is illuminated with the light beam passedthrough the pinhole 138P, and a light-receiving element (light-receivingsystem) 138B which receives the light beam passed through the opticalsystem 138C. For example, a relay optical system may be provided betweenthe optical system 138C and the light-receiving element 138B, and thelight-receiving element 138B may be arranged outside the Z stage 52 aswell. The disclosure of U.S. Pat. No. 4,465,368 is incorporated hereinby reference within a range of permission of the domestic laws andordinances of the designated state or the selected state designated orselected in this international application.

When the illuminance distribution is measured by using the unevenilluminance sensor 138, the space between the projection optical systemPL and the plate member 138A is filled with the liquid in a state inwhich the projection optical system PL is opposed to the plate member138A of the uneven illuminance sensor 138. Subsequently, the pinhole138P is successively moved to a plurality of positions in the radiationarea onto which the exposure light beam is radiated to determine(measure) the illuminance distribution (uneven illuminance) by measuringthe illuminance of the exposure light beam at the respective positionsas described above. After the illuminance distribution is determined,the control unit CONT moves the substrate stage PST to arrange the platemember 138A of the uneven illuminance sensor 138 under the nozzlesection 43 of the first liquid-removing unit 40.

As described above, the liquid-absorbing member 142, which recovers theliquid removed from the plate member 138A by the first liquid-removingunit 40, is provided at the position adjacent to the plate member 138Aon the Z stage 52. The liquid-absorbing member 142 is formed of, forexample, a porous material such as a porous ceramics and a sponge in thesame manner as the liquid-absorbing member 42 described above, which iscapable of retaining a predetermined amount of the liquid.

The control unit CONT blows the gas against the plate member 138A fromthe nozzle section 43 of the first liquid-removing unit 40, and thus theliquid adhered to the plate member 138A is blown off and removed. Theblown off liquid is retained (recovered) by the liquid-absorbing member142 arranged at the position opposed to the blow port 43A of the nozzlesection 43 of the first liquid-removing unit 40. The liquid-repellingtreatment is applied to the surface of the plate member 138A. Therefore,it is possible to avoid any invasion of the liquid into the pinhole138P. Additionally, it is possible to satisfactorily remove the liquidfrom the plate member 138A by allowing the gas to blow thereagainst.

A flow passage 145, which is communicated with the groove 144, is formedin the Z stage 52. The liquid-absorbing member 142 is arranged in thegroove 144 so that the bottom thereof makes contact with the flowpassage 145. The flow passage 145 is connected to one end of a tubepassage 146 which is provided outside the Z stage 52. On the other hand,the other end of the tube passage 146 is connected to a pump 149 via atube passage 148 having a valve 148A and a tank 147 provided outside theZ stage 52. The control unit CONT drives the gas supply section 41A ofthe first liquid-removing unit 40, and the control unit CONT drives thepump 149. Accordingly, the liquid, which is recovered by theliquid-absorbing member 142, is sucked and collected in the tank 147.The tank 147 is provided with a discharge flow passage 147A. When apredetermined amount of the liquid 1 is pooled in the tank 147, theliquid 1 is discharged to the outside from the tank 147 via thedischarge flow passage 147A.

For example, the suction of the liquid and the blowing of the dry airmay be used, or they may be appropriately combined and used, asexplained in the foregoing embodiment in relation to the method forremoving the liquid from the plate member 138A by the firstliquid-removing unit 40. It is unnecessary that the entire surface ofthe plate member 138A is liquid-repellent. It is also allowable thatonly a part of the plate member 138A, for example, only the surroundingof the pinhole 138P may be liquid-repellent. Not only the upper surfaceof the plate member 138A of the uneven illuminance sensor 138 but alsothe surface of another part on the substrate stage PST may beliquid-repellent. It is also allowable that the coating of theliquid-repelling material may be omitted when the ability of the firstliquid-removing unit 40 to remove the liquid is sufficiently high.

Other sensors, which are not limited to the uneven illuminance sensorand which receive the exposure light beam passed via the projectionoptical system PL and the liquid through the light-transmitting portion,are also arranged on the substrate stage PST, including, for example, aradiation amount monitor as disclosed in Japanese Patent ApplicationLaid-open No. 11-16816 (corresponding to United States PatentApplication Publication No. 2002/0061469) and a spatial image-measuringsensor for measuring, for example, the image characteristics asdisclosed in Japanese Patent Application Laid-open No. 2002-14005(corresponding to United States Patent Application Publication No.2002/0041377). The sensors as described above also have such apossibility that the liquid may remain on and adhere to the surface ofthe flat portion formed with the light-transmitting portion. Therefore,it is also allowable to apply, to the sensors, the method for removingthe liquid based on the use of the first liquid-removing unit 40 asdescribed above. When a reflecting member is arranged on the substratestage PST as disclosed in Japanese Patent Application Laid-open No.62-183522 (corresponding to U.S. Pat. No. 4,780,747), it is alsoallowable to remove the liquid remaining on and adhered to the surfacethereof by using the first liquid-removing mechanism 40. The contents ofUnited States Patent Application Publication No. 2002/0061469, UnitedStates Patent Application Publication No. 2002/0041377, and U.S. Pat.No. 4,780,747 are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the designated stateor the selected state designated or selected in this internationalapplication.

When a sensor, which is detachable with respect to the substrate stagePST, is used as disclosed in Japanese Patent Application Laid-open Nos.11-238680 and 2000-97616 and International Publication WO 02/063664(corresponding to United States Patent Application Publication No.2004/0041377), the sensor may be detached from the substrate stage PSTafter removing the liquid remaining on and adhered to the surface of thesensor by using the first liquid-removing unit 40. The disclosure ofUnited States Patent Publication No. 2004/0041377 is incorporated hereinby reference within a range of permission of the domestic laws andordinances of the designated state or the selected state designated orselected in this application.

Embodiment of Exposure Apparatus Based on Use of Third Liquid-RemovingUnit

FIG. 18 schematically shows an exposure apparatus based on the use of athird liquid-removing unit. With reference to FIG. 18, a focus-detectingsystem 4 includes a light-emitting section 4 a and a light-receivingsection 4 b. In this embodiment, those provided in the vicinity of theend portion of the projection optical system PL are a first opticalmember 151 through which a detecting light beam is transmissive, thedetecting light beam being radiated from the light-emitting section 4 aof the focus-detecting system 4, and a second optical member 152 throughwhich the detecting light beam reflected on the substrate P istransmissive. The first optical member 151 and the second optical member152 are supported in a state of being separated from the optical element2 disposed at the end portion of the projection optical system PL. Thefirst optical member 151 is arranged on the −X side of the opticalelement 2, and the second optical member 152 is arranged on the +X sideof the optical element 2. The first and second optical members 151, 152are provided at the positions at which they are capable of makingcontact with the liquid 1 in the liquid immersion area AR2 and at whichthe optical path for the exposure light beam EL and the movement of thesubstrate P are not inhibited.

As shown in FIG. 18, for example, during the exposure process for thesubstrate P, the liquid 1 is supplied and recovered by the liquid supplymechanism 10 and the liquid recovery mechanism 30 so that all of theoptical path of the exposure light beam EL passed through the projectionoptical system PL, i.e., all of the optical path of the exposure lightbeam EL between the optical element 2 and the substrate P (projectionarea AR1 on the substrate P) is filled with the liquid 1. Further, whenall of the optical path of the exposure light beam EL between theoptical element 2 and the substrate P is filled with the liquid 1, andthe liquid immersion area AR2 is formed in a desired state on thesubstrate P to cover all of the projection area AR1, then the liquid 1,which forms the liquid immersion area AR2, makes tight contact (contact)with the end surfaces of the first optical member 151 and the secondoptical member 152 respectively. In the state in which the liquidimmersion area AR2 is formed on the substrate P and the liquid 1 makestight contact with the end surfaces of the first optical member 151 andthe second optical member 152 respectively, all of the optical pathbetween the first optical member 151 and the second optical member 152,which is included in the optical path for the detecting light beamradiated from the light-emitting section 4 a of the focus-detectingsystem 4 and the reflected light beam thereof from the surface of thesubstrate P, is filled with the liquid 1. The setting is made such thatthe detecting light beam, which is radiated from the light-emittingsection 4 a of the focus-detecting system 4, is radiated onto theprojection area AR1 of the projection optical system PL on the substrateP in the state in which all of the optical path for the detecting lightbeam is filled with the liquid 1.

The liquid contact surfaces, which are the end surfaces of the first andsecond optical members 151, 152, are subjected to, for example, theliquid-attracting treatment to have the lyophilicity orliquid-attracting property. Accordingly, the liquid 1 in the liquidimmersion area AR2 tends to easily make tight contact with the liquidcontact surfaces of the first and second optical members 151, 152.Therefore, it is easy to maintain the shape of the liquid immersion areaAR2.

In FIG. 18, the liquid supply mechanism 10 and the liquid recoverymechanism 30 are simplified and illustrated in the drawing. The liquidsupply mechanism 10 shown in FIG. 18 includes a liquid supply section171 which is capable of feeding the liquid 1, and a supply tube 172which connects a supply nozzle 173 and the liquid supply section 171.The liquid 1, which is fed from the liquid supply section 171, passesthrough the supply tube 172, and then the liquid 1 is supplied onto thesubstrate P from a liquid supply port 174 of the supply nozzle 173. Theliquid recovery mechanism 30 shown in FIG. 18 includes a liquid recoverysection 175 which is capable of recovering the liquid 1, and a recoverytube 176 which connects a recovery nozzle 177 and the liquid recoverysection 175. The liquid 1 on the substrate P is recovered from arecovery port 178 of the recovery nozzle 177, and then the liquid 1 isrecovered to the liquid recovery section 175 through the recovery tube176.

This embodiment has been explained assuming that the first opticalmember 151 and the second optical member 152 are mutually independentmembers. However, for example, an annular optical member may be arrangedto surround the optical element 2 disposed at the end portion of theprojection optical system PL. The detecting light beam may be radiatedonto a part of the annular optical member. The detecting light beam,which has passed through the liquid immersion area AR2 and along thesurface of the substrate P, may be received via a part of the annularoptical member. When the optical member is provided in the annular form,and the liquid 1 in the liquid immersion area AR2 is allowed to maketight contact with the inner side surface of the annular optical member,then it is possible to satisfactorily maintain the shape of the liquidimmersion area AR2. In this embodiment, the first optical member 151 andthe second optical member 152 are separated from each other with respectto the projection optical system PL. However, it is also allowable tointegrally provide the first optical member 151, the second opticalmember 152, and the optical element 2 of the projection optical systemPL.

After performing the liquid immersion exposure process in the stateshown in FIG. 18, the control unit CONT arranges the washing plate (or adummy substrate) under the projection optical system PL, for example, asexplained with reference to FIG. 13. The liquid supply mechanism 10 andthe liquid recovery mechanism 30 are used to form the liquid immersionarea AR2 on the washing plate. The liquid 1 in the liquid immersion areaAR2 is used to wash the optical element 2 disposed at the end portion ofthe projection optical system PL, the first and second optical members151, 152, those disposed in the vicinity of the supply port 174 of thesupply nozzle 173, and those disposed in the vicinity of the recoveryport 178 of the recovery nozzle 177. After completing the washing, thecontrol unit CONT uses, for example, the liquid recovery mechanism 30 torecover the liquid 1 of the liquid immersion area AR2.

After recovering the liquid 1 of the liquid immersion area AR2, thecontrol unit CONT arranges a gas nozzle 160 (third liquid-removing unit)for blowing the gas, under the projection optical system PL as shown inFIG. 19 by the aid of an unillustrated driving unit. In this situation,the substrate stage PST is moved to the load/unload position (see FIG.9) in order to unload the substrate P. A liquid-receiving member 280,which receives the liquid 1 fallen, for example, from the opticalelement 2, is arranged under the projection optical system PL. In asituation in which the gas nozzle 160 is not used, the gas nozzle 160 isarranged at a predetermined position in the exposure apparatus (EX) tomake no interference with the substrate stage PST. The gas nozzle 160may be provided at a position other than the position of the substrateholder on the substrate stage PST.

The control unit CONT blows the gas from a blow port 161 of the gasnozzle 160, and the blown liquid is used to move the position of theliquid 1 adhered to the optical element 2, the first and second opticalmembers 151, 152, the supply nozzle 173, and/or the recovery nozzle 177.For example, as shown in FIG. 19, the control unit CONT firstly movesthe blow port 161 of the gas nozzle 160 in parallel to the substratesurface (in the X direction) to arrive at the position opposed to thearea of the lower surface 2 a of the optical element 2 through which theexposure light beam EL passes. After that, the gas is blown from theblow port 161. The gas nozzle 160 is moved toward the outside of thearea through which the exposure light beam EL passes, in a state inwhich the gas is being blown. Accordingly, it is possible to move, tothe outside of the area, the liquid (liquid droplet) 1 adhered to thearea of the lower surface 2 a of the optical element 2 through which theexposure light beam EL passes, i.e., the area of the lower surface 2 aof the optical element 2 corresponding to the projection area AR1. Inthis embodiment, the area, through which the exposure light beam ELpasses, is a substantially central portion of the lower surface 2 a ofthe optical element 2. Therefore, the method as described above can beused to move, toward the end of the lower surface 2 a, the liquid 1adhered to (remaining on) the central portion of the lower surface 2 a(see reference numeral 1′ shown in FIG. 19). In other words, the controlunit CONT removes the liquid adhered to the area through which theexposure light beam EL passes, by moving the liquid to the outside ofthe area by using the blowing gas without drying the liquid 1 adhered tothe area through which the exposure light beam EL passes. Accordingly,it is possible to avoid the inconvenience which would be otherwisecaused such that the water mark is formed in at least the area of thelower surface 2 a of the optical element 2 through which the exposurelight beam EL passes. In this embodiment, the gas nozzle 160 and theunit equipped therewith function as the third liquid-removing unit.

In this embodiment, the liquid is moved aside (removed) from the areathrough which the exposure light beam EL passes. However, there is nolimitation thereto. It is appropriate to move aside the liquid from adesired area, if necessary.

FIG. 20A shows an example of the blow port 161. As shown in FIG. 20A,the blow port 161 is formed to be slit-shaped in which the Y axisdirection is the longitudinal direction in this embodiment. FIG. 20Bshows the lower surface 2 a of the optical element 2. The projectionarea AR1 is slit-shaped (rectangular) in which the Y axis direction isthe longitudinal direction. The blow port 161 is formed to have a sizesmaller than the lower surface 2 a of the optical element 2. When theliquid 1, which is adhered to the central portion of the lower surface 2a of the optical element 2, is moved aside as described above, thecontrol unit CONT firstly allows the gas to blow from the blow port 161in a state in which the blow port 161 of the gas nozzle 160 is opposedto the substantially central portion of the lower surface 2 a of theoptical element 2. The gas nozzle 160 is moved toward the +X side (orthe −X side) while maintaining the gas blowing state. In other words,the control unit CONT moves the gas nozzle 160 in the X axis direction.Accordingly, the control unit CONT can smoothly move (move aside) theliquid 1 to the outside of the area of the lower surface 2 a of theoptical element 2 corresponding to the projection area AR1. When theliquid 1, which is adhered to the central portion of the lower surface 2a of the optical element 2 (central portion of the area corresponding tothe projection area AR1), is moved in the Y axis direction in order toexclude the liquid 1 to the outside of the area corresponding to theprojection area AR1, the movement distance is long, because the Y axisdirection is the longitudinal direction for the projection area AR1.When the movement distance is long, the movement time is long as well.Therefore, when much weight is given to the time efficiency, it isdesirable that the liquid 1, which is adhered to the central portion ofthe lower surface 2 a of the optical element 2 (central portion of thearea corresponding to the projection area AR1), is moved in the X axisdirection. Accordingly, the liquid 1 can be moved smoothly to theoutside of the area corresponding to the projection area AR1.

In this embodiment, the gas, which is blown from the blow port 161 ofthe gas nozzle 160, is the clean gas obtained after passing through afilter unit (not shown) including a chemical filter and aparticle-removing filter. Accordingly, the optical element 2 or the likecan be prevented from being contaminated. As for the gas, it ispreferable to use a gas which is substantially the same as the gascontained in the environment in which the exposure apparatus EX isinstalled, specifically a gas which is substantially the same as the gascontained in the chamber in which the exposure apparatus EX isaccommodated. In this embodiment, the air (dry air) is used.Alternatively, the nitrogen gas (dry nitrogen) may be used as the gaswhich is to be blown. If any gas, which is different from the gascontained in the environment in which the exposure apparatus EX isinstalled, is used, there is such a possibility that any inconveniencesuch as any measurement error or the like may be caused, for example,due to the variation or fluctuation of the optical path for themeasuring light beam of the interferometer which measures the stageposition on account of the difference in refractive index between themutually different gases. However, when the gas, which is blown from theblow port 161, is substantially the same gas as the gas contained in theinstallation environment for the exposure apparatus EX, it is possibleto avoid the inconvenience as described above.

The liquid 1, which has been moved (moved aside) to the outside of thearea through which the exposure light beam EL passes, is vaporized(dried) and removed, for example, by a predetermined drying unit and/orthe gas blown from the gas nozzle 160.

Even when the liquid, which has been moved to the outside of the areathrough which the exposure light beam EL passes, is dried, it ispossible to suppress the adhesion of any impurity or the like to theportion at which the liquid has been dried at the outside of the areathrough which the exposure light beam EL passes, because the washingoperation has been performed for the lower surface 2 a of the opticalelement 2 before allowing the gas to blow from the gas nozzle 160.

In this embodiment, the liquid, which has been moved to the outside ofthe area through which the exposure light beam EL passes, may be sucked(recovered).

Similarly, the control unit CONT moves (move aside) the liquid (liquiddroplet) adhered to at least the area of each of the end surfaces of thefirst and second optical members 151, 152 on the liquid contact surfaceside through which the detecting light beam of the focus-detectingsystem 4 passes, by using the gas blown from the gas nozzle 160.Accordingly, it is possible to avoid the inconvenience which would beotherwise caused such that the water mark is formed in (any impurityadheres to) at least the area of each of the end surfaces of the firstand second optical members 151, 152 through which the detecting lightbeam passes.

Similarly, the control unit CONT moves aside the liquid 1 adhered to(remaining on) the supply nozzle 173 and the recovery nozzle 177 byusing the gas blown from the gas nozzle 160. Accordingly, it is possibleto avoid the inconvenience of the formation of the water mark on thesupply nozzle 173 and the recovery nozzle 177. The water mark acts asthe foreign matter (impurity). Therefore, if the water mark is formed,for example, on the supply nozzle 173 (supply port 174) and/or therecovery nozzle 177 (recovery port 178), there is such a possibilitythat the foreign matter (impurity), which results from the water mark,may invade the liquid immersion area AR2 when the liquid immersion areaAR2 is formed. In such a situation, the exposure accuracy and/or themeasuring accuracy is consequently deteriorated. Further, it isconsidered that the recovery ability of the liquid recovery mechanism 30is changed depending on the contact angle (affinity) of the recoverynozzle 177 (recovery port 178) with respect to the liquid 1. If thewater mark is formed on the recovery nozzle 177, and the contact anglewith respect to the liquid 1 is changed, then there is such apossibility that the recovery ability of the liquid recovery mechanism30 may be deteriorated. However, the inconvenience as described abovecan be avoided by removing the liquid 1 adhered to the nozzles 173, 177as described in this embodiment.

As explained above, the liquid, which adheres to the predetermined areaof the optical element 2 and the first and second optical members 151,152 (area irradiated with the exposure light beam and/or the detectinglight beam), is moved (moved aside) to the outside of the predeterminedarea by blowing the gas thereagainst while moving the gas nozzle 160(blow port 161) relative to the predetermined area. Accordingly, it ispossible to avoid the inconvenience of the formation of the water markin the predetermined area.

This embodiment is constructed such that the gas is firstly blownagainst the central portion of the lower surface 2 a, and then the gasnozzle 160 is moved substantially linearly toward the end of the lowersurface 2 a in the state in which the blow of the gas is maintained,when the liquid 1 adhered to the lower surface 2 a of the opticalelement 2 is moved aside to the end. However, the gas nozzle 160 may bemoved so that the blow port 161 depicts a spiral locus with respect tothe lower surface 2 a. The shape of the blow port 161 is not limited tothe slit-shaped form. It is also allowable to use any arbitrary shapeincluding, for example, circular shapes. Further, a porous member may bearranged at the blow port 161.

In this embodiment, one gas nozzle 160 (blow port 161) is provided. Itis a matter of course that a plurality of gas nozzles 160 (blow ports161) may be provided, and they may be used simultaneously. Further, aplurality of gas nozzles 160 may be used, for example, as follows. Thatis, the liquid 1 adhered to the optical element 2 is removed by usingthe gas blown from the first gas nozzle 160, and the liquid 1 adhered tothe first optical member 151 or the second optical member 152 is removedby using the gas blown from a second gas nozzle 160. The removingoperations as described above may be used concurrently. When theliquid-removing operations are performed concurrently for a plurality ofpredetermined areas by using a plurality of gas nozzles 160respectively, it is possible to efficiently perform the liquid-removingoperations.

In order to move (move aside) the liquid 1 adhered to the end surfacesof the first and second optical members 151, 152 and the optical element2, for example, it is also allowable to use, for example, the gas blownfrom the blow port 64A of the second liquid-removing unit 60 explainedwith reference to FIG. 8.

The embodiment described above is constructed such that the gas is blownfrom the lower position against the optical element 2 and the first andsecond optical members 151, 152. However, the gas may be blown from anupper position. For example, as shown in FIG. 21, a blow port 161 of thegas nozzle 162 may be installed so that the blow port 161 is directeddownwardly or obliquely downwardly to remove (move aside) the liquid 1adhered to the end surface of the second optical member 152 on theliquid contact surface side. It is a matter of course that the gasnozzle 160 can be also used to remove the liquid 1 adhered to the endsurface of the first optical member 151. Alternatively, a flow passage163 may be formed through a part of the first optical member 151 (or thesecond optical member 152). A gas nozzle 164, which is connected to theflow passage 163, may be provided on the end surface of the firstoptical member 151 on the liquid contact surface side. The gas, whichpasses through the flow passage 163 and the gas nozzle 164, can be alsoblown against the end surface of the first optical member 151 from anupper position. The flow passage 163 is formed at a position at whichthe optical path for the detecting light beam of the focus-detectingsystem 4 is not inhibited.

In the embodiment described above, the liquid is removed by using thegas nozzle 160 after washing the optical element 2 disposed at the endportion of the projection optical system PL, the first and secondoptical members 151, 152, those disposed in the vicinity of the supplyport 174 of the supply nozzle 173, and those disposed in the vicinity ofthe recovery port 178 of the recovery nozzle 177. However, the washingstep may be omitted. The gas nozzle 160 may be provided on the substratestage PST in the same manner as in the embodiment described above, andthe gas nozzle 160 may be moved by moving the substrate stage PST.Alternatively, as disclosed in Japanese Patent Application Laid-open No.11-135400, a stage, which is movable on the image plane side of theprojection optical system PL, may be further provided independently fromthe substrate stage PST to arrange the gas nozzle 160 on the stage.

In the embodiment described above, the gas is blown from the blow port161 to move the liquid 1 adhered to the optical element 2, the first andsecond optical members 151, 152, and/or the nozzles 173, 177. However,it is also possible to move the liquid 1 remaining on (adhered to) thesubstrate stage PST by using the gas blown from the blow port 161. Forexample, the blow port 161 may be arranged to be opposed to the uppersurface of the substrate stage PST. The gas may be blown from the blowport 161 against the reference member 7 as explained, for example, withreference to FIG. 3. The liquid 1 adhered onto the reference member 7can be moved (moved aside) to the outside of the reference member 7 (orto the outside of the detection objective area on the reference member7) without drying the liquid 1. Similarly, the gas can be blown from theblow port 161 to move (move aside), without performing the drying, theliquid 1 adhered onto the upper plate 138A of the uneven illuminancesensor 138 as explained, for example, with reference to FIG. 16, and theliquid 1 adhered to a radiation amount monitor as disclosed, forexample, in Japanese Patent Application Laid-open No. 11-16816 and to anupper plate of a spatial image-measuring sensor as disclosed, forexample, in Japanese Patent Application Laid-open No. 2002-14005.

Embodiment of Exposure Apparatus Based on Use of Fourth Liquid-RemovingUnit

FIG. 22 shows an embodiment of an exposure apparatus provided with aliquid-removing unit (fourth liquid-removing unit) different from thefirst to third liquid-removing units. With reference to FIG. 22, one endof a gas supply tube 181 is connected to an intermediate portion of asupply tube 172, for example, by the aid of a flow passage-switchingunit 182 such as a three-way valve. On the other hand, the other end ofthe gas supply tube 181 is connected to a gas supply section 180. Theflow passage-switching unit 182 closes the flow passage which connectsthe gas supply section 180 and a supply port 174 when the flow passage,which connects the liquid supply section 171 and the supply port 174, isopened. On the other hand, the flow passage-switching unit 182 opens theflow passage which connects the gas supply section 180 and the supplyport 174 when the flow passage, which connects the liquid supply section171 and the supply port 174, is closed. Similarly, one end of a gassupply tube 184 is connected to an intermediate portion of a recoverytube 176 by the aid of a flow passage-switching unit 185. The other endof the gas supply tube 184 is connected to a gas supply section 183. Theflow passage-switching unit 185 closes the flow passage which connectsthe gas supply section 183 and a recovery port 178 when the flowpassage, which connects the liquid recovery section 175 and the recoveryport 178, is opened. On the other hand, the flow passage-switching unit185 opens the flow passage which connects the gas supply section 183 andthe recovery port 178 when the flow passage, which connects the liquidrecovery section 175 and the recovery port 178, is closed. In thisembodiment, for example, the gas supply sections 180, 183, the supplyport 174, the recovery port 178, and the flow passage-switching unit 182function as the fourth liquid-removing unit (liquid-removing mechanism)for removing the remaining liquid.

For example, when the liquid immersion area AR2 is formed on thesubstrate P, the control unit CONT drives the flow passage-switchingunits 182, 185 so that the flow passage, which connects the liquidsupply section 171 and the supply port 174, is opened, and the flowpassage, which connects the liquid recovery section 175 and the recoveryport 178, is opened. In this situation, the flow passage for connectingthe gas supply section 180 and the supply port 174, and the flow passagefor connecting the gas supply section 183 and the recovery port 178 areclosed.

After the completion of the liquid immersion exposure for the substrateP, the control unit CONT stops the liquid supply operation performed bythe liquid supply mechanism 10. Further, the liquid recovery operationis continued by the liquid recovery mechanism 30 for a predeterminedperiod of time after the stop of the liquid supply operation to recoverthe liquid 1 with which the liquid immersion area AR2 has been formed.When the liquid supply operation performed by the liquid supplymechanism 10 is stopped, the control unit CONT drives the flowpassage-switching unit 182 to close the flow passage for connecting theliquid supply section 171 and the supply port 174 and open the flowpassage for connecting the gas supply section 180 and the supply port174. After the liquid 1 of the liquid immersion area AR2 substantiallydisappears, the control unit CONT drives the gas supply section 180 tostart the supply of the gas. The gas, which is supplied from the gassupply section 180, is blown from the supply port 174 of the supplynozzle 174 through the gas supply tube 181 and the flowpassage-switching unit 182. Accordingly, the liquid 1, which remains inthe flow passage between the flow passage-switching unit 182 and thesupply port 174, is successfully blown to the outside via the supplyport 174 so that the liquid 1 can be removed. The gas, which is suppliedfrom the gas supply section 180 and which is blown from the supply port174, can be used to remove, for example, the liquid 1 adhered to the endsurfaces of the first and second optical members 151, 152 and the liquid1 adhered onto the substrate stage PST (including, for example, themeasuring member).

Similarly, the control unit CONT drives the flow passage-switching unit185 after the completion of the recovery operation for the liquid 1 inthe liquid immersion area AR2 by the liquid recovery mechanism 30 toclose the flow passage for connecting the liquid recovery section 175and the recovery port 178 and open the flow passage for connecting thegas supply section 183 and the recovery port 178. The control unit CONTuses the gas supplied from the gas supply section 183 so that the liquid1, which remains in the flow passage between the flow passage-switchingunit 185 and the recovery port 178, is blown off to the outside andremoved through the recovery port 178. The gas, which is blown from therecovery port 178, can be also used to remove (move aside) the liquid 1adhered to the end surfaces of the first and second optical members 151,152 and the liquid 1 adhered onto the substrate stage PST (including,for example, the measuring member).

As explained above, the clean gas is supplied from the gas supplysections 180, 183 when the liquid 1 is neither supplied nor recovered.Accordingly, it is possible to avoid the inconvenience of the formationof the water mark in the internal flow passages of the supply tube 172and the supply nozzle 173, those disposed in the vicinity of the supplyport 174, the internal flow passages of the recovery tube 176 and therecovery nozzle 177, and those in the vicinity of the recovery port 178.In this embodiment, the supply port (discharge port) is commonly usedfor the liquid and the gas for removing the liquid. Therefore, thestructure can be simplified in the vicinity of the liquid supply port,and it is possible to obtain the compact exposure apparatus.

Another Embodiment of Exposure Apparatus Based on Use of ThirdLiquid-Removing Unit

FIG. 23 shows a modified embodiment of the exposure apparatus based onthe use of the third liquid-removing unit shown in FIG. 19. Withreference to FIG. 23, a gas nozzle 160, which has a blow port 161, isattached to a liquid-receiving member 190. The liquid-receiving member190 is a dish-shaped member which is formed to be larger than theoccupied area occupied by the optical element 2, the nozzles 173, 177,and the first and second optical members 151, 152. The liquid 1, whichdrips from the respective members, can be received by the upper surfaceof the liquid-receiving member 190. A liquid-absorbing member 199, whichis formed of a porous member or a sponge-like member, is exchangeablyprovided on the upper surface of the liquid-receiving member 190.Accordingly, the liquid 1, which drips from the respective members, canbe satisfactorily recovered (collected) and retained. A circumferentialwall section 191 is formed for the liquid-receiving member 190.Therefore, it is possible to prevent the collected liquid 1 from anyoutflow from the liquid-receiving member 190.

The liquid-receiving member 190 is provided movably by the aid of adriving mechanism 193. The driving mechanism 193 includes an arm section194, an actuator section 195, and a shaft section 196. One end of thearm section 194 is connected to the side surface of the liquid-receivingmember 190, and the other end is connected to the actuator section 195.The actuator section 195 is attached so that the actuator section 195 ishung, for example, by a predetermined support section CL such as acolumn for supporting the projection optical system PL and the body ofthe exposure apparatus EX by the aid of the shaft section 196. When theactuator section 195 is driven, the liquid-receiving member 190, whichis attached to one end of the arm section 194, makes swinging movementin the θZ direction about the swinging center of the shaft section 196.The control unit CONT can move the liquid-receiving member 190 back andforth with respect to the area under the projection optical system PL bydriving the actuator section 195 of the driving mechanism 193 to causethe swinging movement of the liquid-receiving member 190. Further, theactuator section 195 is capable of moving the liquid-receiving member190 in the Z axis direction by the aid of the arm section 194, and theactuator section 195 is capable of moving the liquid-receiving member190 in the XY directions as well.

The liquid-receiving member 190 is provided with an image pickup unit198 including, for example, CCD. The image pickup unit 198 is capable ofoutputting, as an image, the surface information about the opticalelement 2 and the first and second optical members 151, 152.

When the control unit CONT moves (removes) the liquid 1 adhered, forexample, to the optical element 2 and the first and second opticalmembers 151, 152, then the actuator section 195 is driven so that theoptical element 2 is opposed to the liquid-receiving member 190, and thegas is blown against the optical element 2 while moving the gas nozzle160 together with the liquid-receiving member 190 with respect to theoptical element 2. The liquid 1, which adheres to the area of theoptical element 2 corresponding to the optical path for the exposurelight beam EL, is moved by the blown gas, and then the liquid 1 falls.The liquid 1, which has fallen from the optical element 2, is retainedby the liquid-receiving member 190. Accordingly, for example, even whenthe substrate stage PST is arranged under the projection optical systemPL and the liquid-receiving member 190, then the liquid 1 is received bythe liquid-receiving member 190, and thus it is possible to avoid theinconvenience which would be otherwise caused such that the liquid 1,which is removed, for example, from the optical element 2, adheres tothe substrate stage PST.

The control unit CONT controls the gas blow operation of the gas nozzle160 on the basis of the image pickup result obtained by the image pickupunit 198. For example, the control unit CONT determines the position ofthe adhesion of the liquid 1 on the basis of the image pickup resultobtained by the image pickup unit 198 to successfully perform thecontrol such that the position of the adhesion of the liquid 1 and thegas nozzle 160 are subjected to the positional adjustment to allow thegas to blow thereagainst. Accordingly, it is possible to remove theliquid 1 more reliably. When it is judged that the liquid 1 is removedfrom the optical element 2, the control unit CONT completes the gas blowoperation having been performed by the gas nozzle 160.

It is also appropriate to provide a positioning mechanism whichpositions, for example, the liquid-receiving member 190 and the firstand second optical members 151, 152. A leaf spring member 192 as shownby broken lines in FIG. 23 can be used as the positioning mechanism. Inthe illustrative embodiment shown in FIG. 23, the leaf spring member 192is provided on the upper surface 191A of the circumferential wallsection 191 of the liquid-receiving member 190. When theliquid-receiving member 190 is moved in the +Z direction in accordancewith the driving of the actuator section 195 to approach the first andsecond optical members 151, 152, the leaf spring member (positioningmechanism) 192 interposes the outer portions of the first and secondoptical members 151, 152. Accordingly, the first and second opticalmembers 151, 152 and the liquid-receiving member 190 are positioned. Inthis state, the gas, which is discharged from the gas nozzle 160, isblown against a desired area of the optical element 2 (in this case, thearea corresponding to the projection area AR1). Accordingly, it ispossible to satisfactorily remove (move aside) the liquid 1 adhered tothe area.

Still Another Embodiment of Exposure Apparatus Based on Use of ThirdLiquid-Removing Unit

FIG. 24 shows another modified embodiment of the exposure apparatusprovided with the third liquid-removing unit. In this modifiedembodiment, the gas for removing the liquid is jetted or spouted notfrom the nozzle but from suction holes for sucking and attracting thesubstrate. With reference to FIG. 24, the substrate stage PST isprovided with a center table 250 which is provided at a substantiallycentral portion of the substrate stage PST as viewed in a plan view andwhich is movable in the Z axis direction. The center table 250 ismovable in the Z axis direction by the aid of an unillustrated drivingmechanism, which is provided to be capable of protruding from the uppersurface of the substrate stage PST (Z stage 52). The suction holes 251are provided on the upper surface 250A of the center table 250. Thesuction holes 251 are connected to one end of a flow passage 252 whichis provided in the substrate stage PST. On the other hand, the other endof the flow passage 252 is capable of making communication with any oneof one end of a first flow passage 254 and one end of a second flowpassage 255 by the aid of a flow passage-switching unit 253. The otherend of the first flow passage 254 is connected to a vacuum system 256,and the other end of the second flow passage 255 is connected to a gassupply section 257. When the flow passage-switching unit 253 connectsthe flow passage 252 and the first flow passage 254 to open the flowpassage which connects the vacuum system 256 and the suction holes 251,the flow passage-switching unit 253 closes the flow passage whichconnects the gas supply section 257 and the suction holes 251. On theother hand, when the flow passage-switching unit 253 connects the flowpassage 252 and the second flow passage 255 to open the flow passagewhich connects the gas supply section 257 and the suction holes 251, theflow passage-switching unit 253 closes the flow passage which connectsthe vacuum system 256 and the suction holes 251.

When the substrate P is loaded on the substrate stage PST, then thecontrol unit CONT moves the center table 250 upwardly to place thesubstrate P on the center table 250, and the vacuum system 256 is drivento attract and hold the back surface of the substrate P by the aid ofthe suction holes 251. The control unit CONT moves the center table 250downwardly in a state in which the substrate P is attracted and held,and the substrate P is held on the substrate holder on the Z stage 52.The substrate holder is provided, for example, with a pin-chuckmechanism. The substrate holder attracts and holds the substrate P bythe pin-chuck mechanism. On the other hand, when the substrate P isunloaded from the substrate stage PST, then the control unit CONTreleases the substrate P from being attracted and held by the substrateholder, and the center table 250 is moved upwardly while attracting andholding the substrate P. When the center table 250 is moved upwardly ina state in which the substrate P is attracted and held thereby, then thesubstrate P is separated from the Z stage, and the unload operation canbe performed.

In this embodiment, the gas is blown from the suction holes 251 providedfor the center table 250. The blown gas is used to move (move aside) theliquid 1 adhered to the lower surface 2 a of the optical element 2 andthe first and second optical members 151, 152. When the liquid 1 adheredto the optical element 2 and/or the first and second optical members151, 152 is removed, the control unit CONT drives the flowpassage-switching unit 253 to open the flow passage for connecting thegas supply section 257 and the suction holes 251. The control unit CONTmoves the substrate stage PST along the XY plane, while the gas is blownfrom the suction holes 251. When the gas is blown, then the liquid 1,which has been adhered, for example, to the area of the lower surface 2a of the optical element 2 corresponding to the optical path for theexposure light beam EL, is moved, and then the liquid 1 falls.

In this embodiment, a liquid-receiving member DP, which is capable ofcollecting the liquid 1, is installed on the Z stage 52 (substrateholder). The liquid-receiving member DP is a dish-shaped member in thesame manner as the liquid-receiving member 190 shown in FIG. 23, whichis formed to have a circular shape with a size substantially equivalentto that of the substrate P. The liquid-receiving member DP can beinstalled on the substrate holder. The liquid 1, which has fallen fromthe optical element 2, is retained by the liquid-receiving member DPinstalled for the substrate holder. A liquid-retaining member 261 isprovided on the upper surface of the liquid-receiving member DP. Theliquid 1 is recovered and retained by the liquid-retaining member 261.The liquid-receiving member DP has a circumferential wall section 262which prevents the retained liquid 1 from any outflow from theliquid-receiving member DP.

FIG. 25 shows the liquid-receiving member DP held by the substrateholder as viewed from an upper position. With reference to FIG. 25, aplurality of the suction holes 251 are provided on the upper surface250A of the center table 250. In this embodiment, the three suctionholes are provided. A plurality of (three) openings 264, whichcorrespond to the plurality of suction holes 251, are provided for theliquid-receiving member DP. That is, the suction holes 251 are exposedeven in a state in which the liquid-receiving member DP is held by thesubstrate holder. Therefore, the gas, which is discharged or spoutedfrom the suction holes 251, is successfully blown against the opticalelement 2 or the like. A plurality of (three) grooves 258, which extendin the radial direction from the central portion of the upper surface250A, are formed on the upper surface 250A of the center table 250. Theplurality of grooves 258 are continued to one another at the centralportion of the upper surface 250A. The suction holes 251 are arrangedinside the grooves 258. When the back surface of the substrate P as theexposure process objective is attracted and held by the upper surface250A of the center table 250, then the vacuum system 256 is driven in astate in which the back surface of the substrate P abuts against theupper surface 250A, and the space, which is formed by the back surfaceof the substrate P and the grooves 258, is allowed to have a negativepressure. Accordingly, the substrate P can be attracted and held by thecenter table 250. When the liquid-receiving member DP is held by thecenter table 250, the liquid-receiving member DP can be also held by thecenter table 250 by appropriately setting, for example, the shapes andthe sizes of the opening 264 and the groove 258 and/or the size and theposition of the suction hole 251. Alternatively, suction holes andgrooves corresponding thereto, which are different from the suctionholes 251 and which are exclusively used to attract and hold theliquid-receiving member DP, may be previously provided on the uppersurface 250A of the center table 250 (see reference numerals 251′ and258′ shown in FIG. 25). The suction holes 251′ may be used to attractand hold the liquid-receiving member DP with respect to the uppersurface 250A. The center table 250 can be used to load/unload theliquid-receiving member DP with respect to the substrate stage PST, inthe same manner as the substrate P as the exposure process objective.When the liquid removal operation is performed for the optical element 2or the like, the liquid-receiving member DP is loaded on the substratestage PST. When the liquid removal operation is completed, theliquid-receiving member DP is unloaded from the substrate stage PST.When the liquid-receiving member DP is attracted and held by thepin-chuck mechanism of the substrate holder, the following arrangementis adopted in order to form a substantially tightly closed space withrespect to the back surface of the liquid-receiving member DP other thanthe openings 264. That is, for example, the area, which is allowed tohave a negative pressure by the pin-chuck mechanism, may be divided intoa plurality of pieces. The negative pressure is selectively applied inthe area other than the area corresponding to the openings 264.Accordingly, the liquid-receiving member DP can be attracted and heldwith respect to the substrate holder.

There is such a possibility that the liquid 1, which is retained by theliquid-receiving member DP, may invade the space between the backsurface of the liquid-receiving member DP and the upper surface 250A ofthe center table 250 (as well as the upper surface of the substrateholder) via the openings 264. Therefore, it is preferable to provide aseal member, for example, in the vicinity of the openings 264 and/or theback surface of the liquid-receiving member DP in order to avoid theinvasion of the liquid 1.

It is preferable that the substrate stage PST is moved to any positionaway from the projection optical system PL, for example, to theload/unload position B (see FIG. 9) to blow the gas beforehand from thesuction holes 251 at the position before blowing the gas discharged fromthe suction holes 251 against the optical element 2 or the like. Thereis such a possibility that any foreign matter (dust) may be present inthe suction holes 251 and/or in the vicinity of thereof. However, whenthe gas is blown against the optical lens 2 or the like after the gasblow operation is previously performed to remove the foreign matter atthe position separated from the projection optical system PL, it ispossible to avoid the inconvenience such as the pollution of the opticalelement 2 or the like.

Also in the embodiment shown in FIG. 24, the blow port 64A as explained,for example, with reference to FIG. 8 may be provided at any positionother than the position of the substrate holder for holding thesubstrate P on the substrate stage PST, and the gas blown from the blowport 64A can be used to move the liquid 1 adhered to the optical element2 or the like.

In the embodiments described above, the first to fourth liquid-removingunits have been explained. However, each of the removing units asdescribed above may be provided on the exposure apparatus EX singly.Alternatively, the removing units as described above may beappropriately combined and provided on the exposure apparatus EX.

As described above, pure water is used as the liquid 1 in theembodiments of the present invention. Pure water is advantageous in thatpure water is available in a large amount with ease, for example, in thesemiconductor production factory, and pure water exerts no harmfulinfluence, for example, on the optical element (lens) and thephotoresist on the substrate P. Further, pure water exerts no harmfulinfluence on the environment, and the content of impurity is extremelylow. Therefore, it is also expected to obtain the function to wash thesurface of the substrate P and the surface of the optical elementprovided at the end surface of the projection optical system PL.

It is approved that the refractive index n of pure water (water) withrespect to the exposure light beam EL having a wavelength of about 193nm is approximately in an extent of 1.44. When the ArF excimer laserbeam (wavelength: 193 nm) is used as the light source of the exposurelight beam EL, then the wavelength is shortened on the substrate P by1/n, i.e., to about 134 nm, and a high resolution is obtained. Further,the depth of focus is magnified about n times, i.e., about 1.44 times ascompared with the value obtained in the air. Therefore, when it isenough to secure an approximately equivalent depth of focus as comparedwith the case of the use in the air, it is possible to further increasethe numerical aperture of the projection optical system PL. Also in thisviewpoint, the resolution is improved.

In this embodiment, the optical element 2 is attached to the end portionof the projection optical system PL. The lens can be used to adjust theoptical characteristics of the projection optical system PL, including,for example, the aberration (for example, spherical aberration andcomatic aberration). The optical element 2, which is attached to the endportion of the projection optical system PL, may be an optical plate toadjust the optical characteristic of the projection optical system PL.Alternatively, the optical element 2 may be a plane parallel platethrough which the exposure light beam EL is transmissive. When theoptical element 2 to make contact with the liquid 1 is the planeparallel plate which is cheaper than the lens, it is enough that theplane parallel plate is merely exchanged immediately before supplyingthe liquid 1 even when any substance (for example, any silicon-basedorganic matter), which deteriorates the transmittance of the projectionoptical system PL, the illuminance of the exposure light beam EL on thesubstrate P, and the uniformity of the illuminance distribution, isadhered to the plane parallel plate, for example, during the transport,the assembling, and/or the adjustment of the exposure apparatus EX. Anadvantage is obtained such that the exchange cost is lowered as comparedwith the case in which the optical element to make contact with theliquid 1 is the lens. That is, the surface of the optical element tomake contact with the liquid 1 is dirtied, for example, due to theadhesion of scattered particles generated from the resist by beingirradiated with the exposure light beam EL or any adhered impuritycontained in the liquid 1. Therefore, it is necessary to periodicallyexchange the optical element. However, when the optical element is thecheap plane parallel plate, then the cost of the exchange part is low ascompared with the lens, and it is possible to shorten the time requiredfor the exchange. Thus, it is possible to suppress the increase in themaintenance cost (running cost) and the decrease in the throughput.

When the pressure, which is generated by the flow of the liquid 1, islarge between the substrate P and the optical element disposed at theend portion of the projection optical system PL, it is also allowablethat the optical element is tightly fixed so that the optical element isnot moved by the pressure, rather than allowing the optical element tobe exchangeable.

The embodiment of the present invention is constructed such that thespace between the projection optical system PL and the surface of thesubstrate P is filled with the liquid 1. However, for example, anotherarrangement may be adopted such that the space is filled with the liquid1 in a state in which a cover glass constructed of a plane parallelplate is attached to the surface of the substrate P.

The liquid 1 is water in the embodiment of the present invention.However, the liquid 1 may be any liquid other than water. For example,when the light source of the exposure light beam EL is the F₂ laser, theF₂ laser beam is not transmitted through water. Therefore, in this case,those preferably usable as the liquid 1 may include, for example, afluorine-based fluid such as fluorine-based oil and perfluoropolyether(PFPE) through which the F₂ laser beam is transmissive. In this case,the portion to make contact with the liquid 1 is subjected to theliquid-attracting treatment by forming a thin film, for example, with asubstance having a molecular structure of small polarity includingfluorine. Alternatively, other than the above, it is also possible touse, as the liquid 1, liquids (for example, cedar oil) which have thetransmittance with respect to the exposure light beam EL, which have therefractive index as high as possible, and which are stable against thephotoresist coated on the surface of the substrate P and the projectionoptical system PL. Also in this case, the surface treatment is performeddepending on the polarity of the liquid 1 to be used.

When the liquid immersion method is used as described above, thenumerical aperture NA of the projection optical system is 0.9 to 1.3 insome cases. When the numerical aperture NA of the projection opticalsystem is increased as described above, the image formation performanceis sometimes deteriorated by the polarization effect with the randompolarized light beam having been hitherto used as the exposure lightbeam. Therefore, it is desirable to use the polarized illumination. Inthis case, the following procedure is preferred. That is, the linearpolarized illumination is effected, which is adjusted to thelongitudinal direction of the line pattern of the line-and-space patternof the mask (reticle) so that a large amount of diffracted light of theS-polarized component (TE-polarized component), i.e., the component inthe polarization direction along the longitudinal direction of the linepattern is allowed to outgo from the pattern of the mask (reticle). Whenthe space between the projection optical system PL and the resist coatedon the surface of the substrate P is filled with the liquid, thediffracted light of the S-polarized component (TE-polarized component),which contributes to the improvement in the contrast, has thetransmittance through the resist surface that is raised to be high ascompared with a case in which the space between the projection opticalsystem PL and the resist coated on the surface of the substrate P isfilled with the air (gas). Therefore, even when the numerical apertureNA of the projection optical system exceeds 1.0, it is possible toobtain the high image formation performance. It is more effective tomake appropriate combination, for example, with the phase shift maskand/or the oblique incidence illumination method (especially the dipoleillumination method) adjusted to the longitudinal direction of the linepattern as disclosed in Japanese Patent Application Laid-open No.6-188169. For example, when a phase shift mask of the half tone typehaving a transmittance of 6% (pattern having a half pitch of about 45nm) is illuminated by using the linear polarized illumination method andthe dipole illumination method in combination, the depth of focus (DOF)can be increased by about 150 nm as compared with a case in which anyrandom polarized light beam is used, assuming that the illumination σ,which is prescribed by circumscribed circles of two light fluxes forforming the dipole on the pupil plane of the illumination system, is0.95, the radii of the respective light fluxes on the pupil plane are0.125σ, and the numerical aperture of the projection optical system PLis NA=1.2.

Further, for example, when the ArF excimer laser beam is used as theexposure light beam, and the substrate P is exposed with a fineline-and-space pattern (for example, line-and-space of about 25 to 50nm) by using the projection optical system PL having a reductionmagnification of about ¼, then the mask M functions as a polarizingplate on account of the Wave Guide effect depending on the structure ofthe mask M (for example, the pattern fineness and the chromiumthickness), and a large amount of the diffracted light beam of theS-polarized component (TE-polarized component) is radiated from the maskM as compared with the diffracted light beam of the P-polarizedcomponent (TM-component) which lowers the contrast. In such a situation,it is desirable that the linear polarized illumination is used asdescribed above. However, the high resolution performance can beobtained even when the numerical aperture NA of the projection opticalsystem PL is large, for example, 0.9 to 1.3 even when the mask M isilluminated with the random polarized light beam.

When the substrate P is exposed with an extremely fine line-and-spacepattern on the mask M, there is also such a possibility that theP-polarized component (TM-polarized component) may be larger than theS-polarized component (TE-polarized component) on account of the WireGrid effect. However, when the ArF excimer laser beam is used as theexposure light beam, and the substrate P is exposed with aline-and-space pattern larger than 25 nm by using the projection opticalsystem PL having a reduction magnification of about ¼, then a largeamount of the diffracted light beam of the S-polarized component(TE-polarized component) is radiated from the mask M as compared withthe P-polarized component (TM-polarized component). Therefore, the highresolution performance can be obtained even when the numerical apertureNA of the projection optical system PL is large, for example, 0.9 to1.3.

Further, it is also effective to use a combination of the obliqueincidence illumination method and the polarized illumination method inwhich the linear polarization is effected in a tangential(circumferential) direction of a circle having a center of the opticalaxis as disclosed in Japanese Patent Application Laid-open No. 6-53120as well as the linear polarized illumination (S-polarized illumination)adjusted to the longitudinal direction of the line pattern of the mask(reticle). In particular, when the pattern of the mask (reticle)includes not only the line pattern which extends in a predetermined onedirection but the pattern also includes line patterns which extend in aplurality of directions in a mixed manner, then the high image formationperformance can be obtained even when the numerical aperture NA of theprojection optical system is large, by using, in combination, the zonalillumination method and the polarized illumination method in which thelinear polarization is effected in a tangential direction of a circlehaving a center of the optical axis as disclosed in Japanese PatentApplication Laid-open No. 6-53120 as well. For example, when a phaseshift mask of the half tone type (pattern having a half pitch of about63 nm) having a transmittance of 6% is illuminated by using, incombination, the zonal illumination method (zonal ratio: 3/4) and thepolarized illumination method in which the linear polarization iseffected in a tangential direction of a circle having a center of theoptical axis, the depth of focus (DOF) can be increased by about 250 nmas compared with a case in which any random polarized light beam isused, assuming that the illumination σ is 0.95, and the numericalaperture of the projection optical system PL is NA=1.00. When thenumerical aperture of the projection optical system is NA=1.2 with apattern having a half pitch of about 55 nm, it is possible to increasethe depth of focus by about 100 nm.

The substrate P, which is usable in the respective embodiments describedabove, is not limited to the semiconductor wafer for producing thesemiconductor device. Those applicable include, for example, the glasssubstrate for the display device, the ceramic wafer for the thin filmmagnetic head, and the master plate (synthetic quartz, silicon wafer)for the mask or the reticle to be used for the exposure apparatus.

As for the exposure apparatus EX, the present invention is alsoapplicable to the scanning type exposure apparatus (scanning stepper)based on the step-and-scan system for performing the scanning exposurefor the pattern of the mask M by synchronously moving the mask M and thesubstrate P as well as the projection exposure apparatus (stepper) basedon the step-and-repeat system for performing the full field exposure forthe pattern of the mask M in a state in which the mask M and thesubstrate P are allowed to stand still, while successively step-movingthe substrate P. The present invention is also applicable to theexposure apparatus based on the step-and-stitch system in which at leasttwo patterns are partially overlaid and transferred on the substrate P.

The present invention is also applicable to a twin-stage type exposureapparatus. The structure and the exposure operation of the twin-stagetype exposure apparatus are disclosed, for example, in Japanese PatentApplication Laid-open Nos. 10-163099 and 10-214783 (corresponding toU.S. Pat. Nos. 6,341,007, 6,400,441, 6,549,269, and 6,590,634),Published Japanese Translation of PCT International Publication forPatent Application No. 2000-505958 (corresponding to U.S. Pat. No.5,969,441), and U.S. Pat. No. 6,208,407, contents of which areincorporated herein by reference within a range of permission of thedomestic laws and ordinances of the state designated or selected in thisinternational application.

The embodiments described above adopt the exposure apparatus in whichthe space between the projection optical system PL and the substrate Pis locally filled with the liquid. However, the present invention isalso applicable to a liquid immersion exposure apparatus wherein astage, which holds the substrate as the exposure objective, is moved ina liquid bath. For example, Japanese Patent Application Laid-open No.6-124873 discloses the structure and the exposure operation of theliquid immersion exposure apparatus wherein the stage, which holds thesubstrate as the exposure objective, is moved in the liquid bath. Forexample, U.S. Pat. No. 5,825,043 (Japanese Patent Application Laid-openNo. 10-303114) discloses an exposure apparatus wherein a liquid bath isformed on a substrate stage to hold the substrate therein. The contentsof the description in U.S. Pat. No. 5,825,043 are incorporated herein byreference within a range of permission of the domestic laws andordinances of the state designated or selected in this internationalapplication.

As for the type of the exposure apparatus EX, the present invention isnot limited to the exposure apparatus for the semiconductor deviceproduction apparatus for exposing the substrate P with the semiconductordevice pattern. The present invention is also widely applicable, forexample, to the exposure apparatus for producing the liquid crystaldisplay device or for producing the display as well as the exposureapparatus for producing, for example, the thin film magnetic head, theimage pickup device (CCD), the reticle, or the mask.

When the linear motor is used for the substrate stage PST and/or themask stage MST, it is allowable to use any one of those of the airfloating type based on the use of the air bearing and those of themagnetic floating type based on the use of the Lorentz's force or thereactance force. Each of the stages PST, MST may be either of the typein which the movement is effected along the guide or of the guidelesstype in which no guide is provided. An example of the use of the linearmotor for the stage is disclosed in U.S. Pat. Nos. 5,623,853 and5,528,118, contents of which are incorporated herein by reference withina range of permission of the domestic laws and ordinances of the statedesignated or selected in this international application.

As for the driving mechanism for each of the stages PST, MST, it is alsoallowable to use a plane motor in which a magnet unit provided withtwo-dimensionally arranged magnets and an armature unit provided withtwo-dimensionally arranged coils are opposed to one another, and each ofthe stages PST, MST is driven by the electromagnetic force. In thisarrangement, any one of the magnet unit and the armature unit isconnected to the stage PST, MST, and the other of the magnet unit andthe armature unit is provided on the side of the movable surface of thestage PST, MST.

The reaction force, which is generated in accordance with the movementof the substrate stage PST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL. The method for handlingthe reaction force is disclosed in detail, for example, in U.S. Pat. No.5,528,118 (Japanese Patent Application Laid-open No. 8-166475), contentsof which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

The reaction force, which is generated in accordance with the movementof the mask stage MST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL. The method for handlingthe reaction force is disclosed in detail, for example, in U.S. Pat. No.5,874,820 (Japanese Patent Application Laid-open No. 8-330224), contentsof which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

As described above, the exposure apparatus EX according to theembodiment of the present invention is produced by assembling thevarious subsystems including the respective constitutive elements asdefined in claims so that the predetermined mechanical accuracy, theelectric accuracy, and the optical accuracy are maintained. In order tosecure the various accuracies, those performed before and after theassembling include the adjustment for achieving the optical accuracy forthe various optical systems, the adjustment for achieving the mechanicalaccuracy for the various mechanical systems, and the adjustment forachieving the electric accuracy for the various electric systems. Thesteps of assembling the various subsystems into the exposure apparatusinclude, for example, the mechanical connection, the wiring connectionof the electric circuits, and the piping connection of the air pressurecircuits in correlation with the various subsystems. It goes withoutsaying that the steps of assembling the respective individual subsystemsare performed before performing the steps of assembling the varioussubsystems into the exposure apparatus. When the steps of assembling thevarious subsystems into the exposure apparatus are completed, theoverall adjustment is performed to secure the various accuracies as theentire exposure apparatus. It is desirable that the exposure apparatusis produced in a clean room in which, for example, the temperature andthe cleanness are managed.

As shown in FIG. 26, the microdevice such as the semiconductor device isproduced by performing, for example, a step 201 of designing thefunction and the performance of the microdevice, a step 202 ofmanufacturing a mask (reticle) based on the designing step, a step 203of producing a substrate as a base material for the device, an exposureprocess step 204 of exposing the substrate with a pattern of the mask byusing the exposure apparatus EX of the embodiment described above, astep 205 of assembling the device (including a dicing step, a bondingstep, and a packaging step), and an inspection step 206.

According to the present invention, it is possible to avoid theoccurrence of the rust or the like on the apparatus and theenvironmental change in the exposure apparatus caused by the falling ofthe remaining liquid, by removing the unnecessary liquid remaining onthe part arranged in the vicinity of the image plane of the projectionoptical system. In particular, it is possible to avoid the occurrence ofthe adhesion trace (water mark) on the optical element, by removing theliquid remaining on the optical element disposed at the end portion ofthe projection optical system. Therefore, it is possible to accuratelyform a desired pattern on the substrate.

What is claimed is:
 1. A lens cleaning module for a liquid immersionlithography system having an exposure apparatus including an objectivelens, comprising: an immersion fluid supply system from which animmersion liquid is supplied to fill a space between a wafer and theobjective lens in a liquid immersion lithography process; a scanningstage by which the wafer is supported beneath the objective lens; and acleaning module coupling with the liquid immersion lithography systemfor cleaning the objective lens in a cleaning process, the cleaningmodule comprising a member and the member being moved below theobjective lens, wherein the immersion liquid is supplied from theimmersion fluid supply system to a space between the objective lens anda surface of the member to clean the objective lens in the cleaningprocess.
 2. The lens-cleaning module of claim 1, wherein the cleaningmodule further comprises a cleaning fluid supply system for providing acleaning fluid.
 3. The lens-cleaning module of claim 2, wherein thecleaning module comprises a part for collecting or removing the usedcleaning fluid.
 4. The lens-cleaning module of claim 3, furthercomprising a drying module associated with the cleaning module fordrying the objective lens.
 5. The lens-cleaning module of claim 1,wherein the exposure apparatus has a light source which emits lighthaving a wavelength of less than about 250 nm.
 6. The lens-cleaningmodule of claim 1, wherein the objective lens has an NA of greater thanabout 0.75.
 7. The lens-cleaning module of claim 2, wherein the cleaningfluid supply system supplies the cleaning fluid on the objective lens.8. The lens-cleaning module of claim 2, wherein the cleaning fluid is acleaning liquid.
 9. The lens-cleaning module of claim 2, wherein thecleaning module includes a nozzle that emits a stream of the cleaningfluid directly onto the surface of the objective lens.
 10. Thelens-cleaning module of claim 9, wherein the cleaning fluid is acleaning liquid.
 11. A method for patterning semiconductor wafers byimmersion lithography to improve exposure quality comprising: filling animmersion liquid between a semiconductor wafer on a stage of animmersion lithography apparatus and an objective lens of the immersionlithography apparatus; exposing the semiconductor wafer to a lightsource having a wavelength of less than about 250 nm through theimmersion liquid; and cleaning a surface of the objective lens after theexposing utilizing a lens cleaning module, wherein the lens cleaningmodule includes a member, which is moved below the objective lens, andwherein the immersion liquid is supplied to a space between theobjective lens and a surface of the member to clean the objective lens.12. The method according to claim 11, wherein the lens cleaning modulefurther comprises a cleaning fluid distribution supply system.
 13. Themethod according to claim 12, wherein the lens cleaning module furthercomprises a cleaning fluid removing/collecting system.
 14. The method ofclaim 12, wherein the cleaning fluid is a cleaning liquid.
 15. Themethod of claim 12, wherein the cleaning module includes a nozzle thatemits a stream of the cleaning fluid directly onto the surface of theobjective lens.
 16. The method of claim 15, wherein the cleaning fluidis a cleaning liquid.
 17. A method for patterning semiconductor wafersby immersion lithography to improve exposure quality comprising:utilizing a lens cleaning module to clean a surface of an objective lensbefore wafer exposure processing, the lens cleaning module comprising amember and the member being moved below the objective lens; filling animmersion liquid between a semiconductor wafer on a stage of animmersion lithography apparatus and the objective lens of the immersionlithography apparatus; and exposing the semiconductor wafer to a lightsource having a wavelength of less than about 250 nm through theimmersion liquid, wherein the immersion liquid is supplied to a spacebetween the surface of the objective lens and a surface of the member toclean the surface of the objective lens.
 18. The method according toclaim 17, wherein the lens cleaning module further comprises a cleaningfluid distribution supply system.
 19. The method according to claim 18,wherein the lens cleaning module further comprises a cleaning fluidremoving/collecting system.
 20. The method of claim 18, wherein thecleaning fluid is a cleaning liquid.
 21. The method of claim 18, whereinthe cleaning module includes a nozzle that emits a stream of thecleaning fluid directly onto the surface of the objective lens.
 22. Themethod of claim 21, wherein the cleaning fluid is a cleaning liquid. 23.A lens cleaning module for a liquid immersion lithography system havingan exposure apparatus including an objective lens, comprising: animmersion fluid supply system from which an immersion liquid is suppliedto fill a space between a wafer and the objective lens in a liquidimmersion lithography process; a scanning stage by which the wafer issupported beneath the objective lens; a cleaning module coupling withthe lithography system for cleaning the objective lens in a cleaningprocess, the cleaning module comprising a member and the immersionliquid being supplied to a space between the objective lens and themember to clean the objective lens in the cleaning process; and a dryingmodule associated with the cleaning module for drying the objectivelens.
 24. The lens-cleaning module of claim 23, wherein the cleaningmodule comprises a part collecting or removing a used cleaning fluid.25. The lens cleaning module of claim 23, wherein the cleaning moduleutilizes a distribution mechanism for distributing a cleaning fluid onthe objective lens.
 26. The lens cleaning module of claim 23, furthercomprising: a collecting system for collecting a cleaning fluid.
 27. Amethod for patterning semiconductor wafers by immersion lithography toimprove exposure quality comprising: filling an immersion liquid betweena semiconductor wafer on a stage of a liquid immersion lithographyapparatus and an objective lens of the liquid immersion lithographyapparatus; exposing the semiconductor wafer to a light source having awavelength of less than about 250 nm through the immersion liquid; andcleaning a surface of the objective lens after the exposing utilizing alens cleaning module, the lens cleaning module comprising a cleaningfluid removing/collecting system and a member and the member being movedbelow the objective lens, wherein the immersion liquid is supplied to aspace between the objective lens and a surface of the member to cleanthe objective lens.
 28. A method for patterning semiconductor wafers byimmersion lithography to improve exposure quality comprising: utilizinga lens cleaning module to clean a surface of an objective lens beforewafer exposure processing, the lens cleaning module comprising acleaning fluid removing/collecting system and a member and the memberbeing moved below the objective lens; filling an immersion liquidbetween a semiconductor wafer on a stage of a liquid immersionlithography apparatus and the objective lens of the liquid immersionlithography apparatus; and exposing the semiconductor wafer to a lightsource having a wavelength of less than about 250 nm through theimmersion liquid, wherein the immersion liquid is supplied to a spacebetween the surface of the objective lens and a surface of the member toclean the surface of the objective lens.